Chronic atrioventricular nodal vagal stimulation --- first evidence for long-term ventricular rate control in canine atrial fibrillation model

We have previously demonstrated that selective atrioventricular nodal (AVN) vagal stimulation (AVN-VS) can be used to control ventricular rate during atrial fibrillation (AF) in acute experiments. However, it is not known whether this approach could provide a long-term treatment in conscious animals. Thus, this study reports the first observations on the long-term efficacy and safety of this novel approach to control ventricular rate during AF in chronically instrumented dogs. In 18 dogs, custom-made bipolar patch electrodes were sutured to the epicardial AVN fat pad for delivery of selective AVN-VS by a subcutaneously implanted nerve stimulator (pulse width 100 micros or 1 ms, frequency 20 or 160 Hz, amplitude 6 to 10 V). Fast-rate right atrial pacing (600 bpm) was used to induce and maintain AF. ECG, blood pressure, and body temperature were monitored telemetrically. One week after the induction of AF, AVN-VS was delivered and maintained for at least 5 weeks. It was found that AVN-VS had a consistent effect on ventricular rate slowing (on average 45+/-13 bpm) over the entire period of observation. Echocardiography showed improvement of cardiac indices with ventricular rate slowing. AVN-VS was well tolerated by the animals, causing no signs of distress or discomfort. Beneficial long-term ventricular rate slowing during AF can be achieved by implantation of a nerve stimulator attached to the epicardial AVN fat pad. This novel concept is an attractive alternative to other methods of rate control and may be applicable in a selected group of patients.


The Left Atrial Appendage, a Small, Blind-Ended Structure. A Review of Its Echocardiographic Evaluation and Its Clinical Role

The increasing prevalence of stroke and atrial fibrillation is a stimulus for new therapeutic strategies and also warrants a review of imaging modalities of the most important source of cardiac systemic embolic events: the left atrial appendage (LAA). This blind-ended, complex structure is embryologically distinct from the body of the left atrium and is sometimes regarded as just a minor extension of the atrium. However, it should routinely be analyzed as part of a transesophageal echocardiographic (TEE) examination. A pulsed Doppler TEE analysis of LAA emptying flow should supplement a two-dimensional (2-D) analysis; these examinations have proven to be highly reproducible and to help assess thromboembolic risk. In 2-D imaging, potential thrombus and spontaneous echo contrast should be sought. In addition, LAA plays a hemodynamic role that participates in atrial function and is influenced by various hemodynamic conditions. In view of the embolic risks from a dysfunctional appendage, the LAA is often ligated during cardiac valve surgery. New devices are under evaluation for percutaneous closure of the LAA, and further studies should improve the definition, understanding, and treatment of LAA dysfunction.


Differences in left ventricular long-axis function from mice to humans follow allometric scaling to ventricular size.

While the heart size maintains a constant proportion to body size, heart function parameters, such as heart rate and cardiac output, show a more complex scaling pattern. How these phenomena affect the long-axis left ventricular (LV) function is unknown. We studied 10 mice, 15 rats, 6 rabbits, 8 mongrel dogs and 38 human volunteers. Doppler tissue echocardiography data were postprocessed to reconstruct mitral annulus (MA) peak systolic velocity and displacement. The relationship between MA peak velocity, MA displacement and LV ejection time, and LV end-diastolic volume (and mass) were fit to an allometric (power-law) equation Y=kMbeta. LV mass varied from 0.062 to 255 g, while end-diastolic volume varied from 0.014 to 205 ml. beta values of the relation between LV ejection time and LV end-diastolic volume and mass were 0.247+/-0.017 and 0.267+/-0.018, respectively. beta values of the relationship between MA displacement and LV end-diastolic volume and mass were 0.358+/-0.047 and 0.390+/-0.051 (P<0.023 versus beta of LV ejection time). beta values of the relationship between MA peak systolic velocity and LV end-diastolic volume and mass were 0.096+/-0.012 and 0.100+/-0.013, respectively (P<0.0001 versus 0). Finally, beta values of the relationship between the long-to-short axis displacement ratio and LV end-diastolic volume and mass were 0.077+/-0.017 and 0.086+/-0.019 (P<0.0001 versus 0). We conclude that MA velocity, displacement, and long-to-short axis displacement ratio scale allometrically to heart size. This reduces the relative long-axis contribution to heart function in small mammals.


Usefulness of Doppler assessment of pulmonary vein and left atrial appendage flow following pulmonary vein isolation of chronic atrial fibrillation in predicting recovery of left atrial function

Atrial fibrillation (AF) is a widespread condition that causes significant morbidity and mortality. Recently, pulmonary venous (PV) isolation using radiofrequency ablation has been used successfully to exclude the pulmonary venous ostia, resulting in correction of AF. Further, miniaturized high-frequency ultrasound phased-array transducers currently provide Doppler and 2-dimensional imaging during the ablation procedure. We examined atrial function and its determinants using intracardiac echocardiography before and after PV isolation in 45 patients who had chronic AF (56 +/- 11 years old). PV, left atrial (LA) appendage, and mitral and tricuspid flows were recorded. Recovery of booster pump function (defined by the presence of mitral inflow A wave, LA appendage a-wave, and PV A-reversal wave velocities >10 cm/s) was observed in 39 of 45 patients (86.6%). PV flow systolic wave before and after ablation correlated with the degree of LA booster pump function after PV isolation. An early systolic PV flow peak velocity >57.47 cm/s predicted "good" LA booster pump function recovery with 96% specificity. Diastolic LA appendage emptying in AF correlated (p <0.001) and predicted good LA booster pump function with 92% specificity for velocities >46.4 cm/s. Thus, monitoring LA function during PV isolation for chronic AF is feasible. Most patients recovered LA booster pump function immediately after PV isolation, and the degree of recovery correlated with LA reservoir function. Preserved reservoir function during AF is predictive of satisfactory recovery of booster pump function after PV isolation.


Automated mitral annular tracking --- a novel method for evaluating mitral annular motion using two-dimensional echocardiography

We developed an automated mitral annular tracking method based on a digital processing of high frame rate cineloop images of 2-dimensional echocardiography. In this study, its feasibility and accuracy was validated in 11 healthy volunteers and 16 patients with left ventricular (LV) dysfunction. The mitral annular excursion measured by automated mitral annular tracking agreed well with that measured by 3-dimensional echocardiography and correlated with LV ejection fraction. The longitudinal mitral annular excursion was reduced whereas the radial one was preserved for patients with LV dysfunction compared with control subjects. The novel automated mitral annular tracking method is clinically feasible and has potential capability to quantify the comprehensive mitral annular motion for evaluating LV function in a clinical setting.

Journal of the American Society of Echocardiography


組織ドプラー法による左室機能の評価

組織ドプラー法による左室機能の評価

The Journal of Japan Society for Clinical Anesthesia


Assessment of left ventricular torsional deformation by Doppler tissue imaging --- validation study with tagged magnetic resonance imaging

Left ventricular (LV) torsional deformation is a sensitive index for LV performance but difficult to measure. The present study tested the accuracy of a novel method that uses Doppler tissue imaging (DTI) for quantifying LV torsion in humans with tagged magnetic resonance imaging (MRI) as a reference. Twenty patients underwent DTI and tagged MRI studies. Images of the LV were acquired at apical and basal short-axis levels to assess LV torsion. We calculated LV rotation by integrating the rotational velocity, determined from DTI velocities of the septal and lateral regions, and correcting for the LV radius over time. LV torsion was defined as the difference in LV rotation between the 2 levels. DTI rotational and torsional profiles throughout systole and diastole were compared with those by tagged MRI at isochronal points. Rotation and torsion by DTI were closely correlated with tagged MRI results during systole and early diastole (apical and basal rotation, r=0.87 and 0.90, respectively; for torsion, 0.84; P<0.0001, by repeated-measures regression models). Maximal torsion showed even better correlation (r=0.95, P<0.0001). The present study has shown that DTI can quantify LV torsional deformation over time. This novel method may facilitate noninvasive quantification of LV torsion in clinical and research settings.


最大酸素摂取量と血中ホモシステインとの関連性:トータル·ヘルス·プロモーション·プラン検診による検討

トータル·ヘルス·プロモーション·プランによる健康づくりにより，ホモシステイン濃度の低下がみられ，動脈硬化を減少させると考えられた．


Coupled pacing improves cardiac efficiency during acute atrial fibrillation with or without cardiac depression

Coupled pacing (CP), a method for controlling ventricular rate during atrial fibrillation (AF), consists of a single electrical stimulation applied to the ventricles after each spontaneous activation. CP results in a mechanical contraction rate approximately one-half the rate during AF. Paired stimulation in which two electrical stimuli are delivered to the ventricles has also been proposed as a therapy for heart failure. Although paired stimulation enhances contractility, it greatly increases energy consumption. The primary hypothesis of the present study is that CP improves cardiac function during acute AF without a similar increase in energy consumption because of the reduced rate of ventricular contractions. In a canine model, CP was applied during four stages: sinus rhythm (SR), acute AF, cardiac dysfunction (CD), and AF in the presence of cardiac dysfunction. The rate of ventricular contraction decreased in all four stages as the result of CP. In addition, we determined the changes in external cardiac work, myocardial oxygen consumption, and myocardial efficiency in the each of four stages. CP partially reversed the effects of AF and CD on external cardiac work, whereas myocardial oxygen consumption increased only moderately. In all stages but SR, CP increased myocardial efficiency because of the marked increases in cardiac work compared with the moderate increases in total energy consumed. Thus this pacing therapy may be a viable therapy for patients with concurrent atrial fibrillation and heart failure.

American Journal of Physiology, Heart and Circulatory Physiology


Usefulness of intracardiac Doppler assessment of left atrial function immediately post-pulmonary vein antrum isolation to predict short-term recurrence of atrial fibrillation

Doppler assessments of pulmonary venous (PV) and left atrial appendage flows are useful surrogates of left atrial (LA) function, but it is unknown if these can predict atrial fibrillation (AF) recurrence after pulmonary vein antrum isolation. We compared Doppler surrogates of LA function immediately after pulmonary vein antrum isolation in patients with AF recurrence versus matched patients without recurrence. Patients with a 6-month recurrence had significantly lower LA appendage peak emptying velocity (19 +/- 10 vs 29 +/- 11 cm/s) and lower peak PV systolic wave velocity (36 +/- 17 vs 46 +/- 22 cm/s) compared with those without, suggesting that intracardiac Doppler assessment of LA function after AF ablation predicts AF recurrence.


Frank-Starling mechanism contributes modestly to ventricular performance during atrial fibrillation

The aim of this study was to assess whether Frank-Starling mechanism has an independent effect on left ventricular (LV) performance in atrial fibrillation (AF). Ventricular performance in AF depends on variable contractility through the interval-force mechanism based on the ratio of preceding and pre-preceding RR intervals (RR(p)/RR(pp)). The impact of end-diastolic volume (EDV) variability, through the Frank-Starling mechanism, is not well understood. We induced AF in 16 open chest dogs. RR intervals, LV pressure, LV volume, and aortic flow were collected for >400 beats during rapid AF (ventricular cycle length 292 +/- 66 ms). In six of the dogs, additional data were collected while average ventricular cycle length was prolonged from 258 +/- 34 ms to 445 +/- 80 ms by selective vagal nerve stimulation of the AV node. The relations of maximal LV power (LVPower) and peak LV pressure derivative (dP/dt) versus RR(p)/RR(pp) were fitted to the equation y = A * (1 - EXP (RR(p)/RR(pp)min - RR(p)/RR(pp))/C) and the residuals (RES) of these relations were analyzed. LVPower and dP/dt strongly correlated with RR(p)/RR(pp) (r(2) = 0.67 +/- 0.12 and 0.66 +/- 0.12, P < .0001 for all correlations). Importantly, RES-LVPower and RES-dP/dt showed linear correlation with EDV (r(2) = 0.20 +/- 0.14 and r(2) = 0.24 +/- 0.17, P < .01 for all correlations). In the six dogs with slowed average ventricular rate, the slope of both residual relationships (RES-LVPower vs EDV and RES- dP/dt vs EDV) decreased (P < .03 for both). The Frank-Starling mechanism contributes to ventricular performance in AF independently of the interval-force effects of the beat-to-beat variability in cardiac contractility. The Frank-Starling mechanism is sensitive to the average ventricular rate.


Losartan improves regional left ventricular systolic and diastolic function in patients with hypertension --- Accurate evaluation using a newly developed color-coded tissue Doppler imaging technique

Angiotensin II receptor antagonists have recently been accepted as antihypertensive therapy. Tissue Doppler imaging (TDI) has been developed as a noninvasive tool to assess quantitatively regional myocardial motion abnormalities. This study was designed to determine whether our newly developed technique of color-coded TDI may be a useful means of quantifying the improvement in regional left ventricular (LV) myocardial contractility and relaxation after treatment with losartan in patients with hypertension. Losartan (50 to 100 mg) was administered for 6 months to 37 previously untreated patients with essential hypertension. Averaged myocardial velocity profiles (MVPs) for color-coded TDI were recorded in the ventricular septum and LV posterior wall before and after treatment. Peak myocardial velocities and peak myocardial velocity gradients (MVGs) in the LV walls were determined during systole and early diastole. The plasma concentration of transforming growth factor (TGF)-beta1 also was measured in all patients. Blood pressure and plasma TGF-beta1 level decreased after initiation of losartan therapy. The LV mass index and LV meridional end-systolic wall stress also decreased after treatment with losartan. LV geometry changed from a pattern consistent with concentric hypertrophy to normal geometry in 10 patients and to a pattern consistent with concentric remodeling in 5 patients, and from concentric remodeling to normal geometry in 5 patients after treatment with losartan. The ratio of early to late diastolic filling for the transmitral flow velocity increased after losartan treatment. The peak systolic and early diastolic myocardial velocities and MVGs in the ventricular septum and LV posterior wall increased after treatment with losartan, although the values 6 months after treatment with losartan were still lower than those in normal individuals. There were good correlations between changes in plasma TGF-beta1 level and changes in systolic and early diastolic MVGs 6 months after losartan. However, there were no significant correlations between changes in the systolic blood pressure and LV end-systolic wall stress and changes in the TDI parameters. Losartan improves regional LV function in patients with hypertension. Our newly developed averaged MVP and MVG measurements may be useful for accurately evaluating regional LV myocardial contractility and relaxation in these patients.


The "Pseud-Restrictive" Pattern of Transmitral Doppler Flow Pattern Following Conversion of Atrial Fibrillation to Sinus Rhythm --- Is Atrial or Ventricular Dysfunction to Blame?

Patients with paroxysmal atrial fibrillation (AF) who have recently converted from AF to sinus rhythm often exhibit a restrictive Doppler pattern in the transmitral flow (TMF) velocity. However, the mechanism of this phenomenon has not been well defined. We evaluated the temporal change of TMF pattern and hemodynamics after conversion of AF to in sinus rhythm in an animal model. Eight open-chest dogs underwent 3 hours of pacing-induced AF. TMF velocities and pressure data were acquired at baseline (sinus rhythm), immediately after conversion of AF, and every 10 minutes thereafter. Early diastolic TMF velocity was increased immediately after conversion and recovered to the baseline value in 20 minutes. Atrial systolic TMF velocity was reduced after AF and recovered to baseline value in 20 to 30 minutes. Early diastolic/atrial systolic TMF velocity was increased after conversion, and recovered to baseline value in 20 to 30 minutes. The mean left atrial (LA) pressure increased immediately, 10 and 20 minutes after the conversion of AF to sinus rhythm. The left ventricular end-diastolic pressure was increased and positive left ventricular dP/dt and tau were decreased immediately after AF, whereas they recovered within 10 minutes. In conclusion, a pseudorestrictive pattern of TMF after AF occurred as a result of transient LA mechanical functional impairment and increased LA pressure caused by LA stunning. Transient left ventricular diastolic dysfunction also effected the TMF velocity immediately after the conversion from AF to sinus rhythm, although it recovered faster than LA mechanical dysfunction.

Journal of the American Society of Echocardiography


Diagnosis of cardiac amyloidosis based on the myocardial velocity profile in the hypertrophied left ventricular wall.

The myocardial velocity profile (MVP), derived from color-coded tissue Doppler imaging (TDI), can identify transmural heterogeneity based on the physiology and pathology of the myocardium. This study sought to clarify whether the MVP can differentiate cardiac amyloidosis from other causes of left ventricular hypertrophy. We recorded the MVP and determined its myocardial velocity gradient (MVG) in the ventricular septum and left ventricular posterior wall using color-coded TDI in 10 patients with cardiac amyloidosis, in 25 patients with hypertensive hypertrophied left ventricular wall, in 25 patients with asymmetric septal hypertrophy of hypertrophic cardiomyopathy, and in 20 clinically normal controls. End-diastolic ventricular septal thickness was similar among the cardiac amyloidosis, hypertension, and hypertrophic cardiomyopathy groups. Percent systolic thickening of the ventricular septum and left ventricular posterior wall calculated from M-mode left ventricular echocardiograms was lower in the cardiac amyloidosis group than in the hypertension, hypertrophic cardiomyopathy, or control group. Peak MVGs during systole and early diastole were lowest in the cardiac amyloidosis group, followed, in order, by the control, hypertension, and hypertrophic cardiomyopathy groups. The systolic and early diastolic MVPs in the ventricular septum and left ventricular posterior wall showed a characteristic serrated pattern in all patients with cardiac amyloidosis, but not in any other patient groups. In conclusion, MVPs in the ventricular septum and left ventricular posterior wall show a distinctive serrated pattern that may be related to amyloid deposition in the myocardium. Myocardial tissue characterization using color-coded TDI provides diagnostic information in patients with cardiac amyloidosis.


Potential application of tissue Doppler imaging to assess regional left ventricular diastolic function in patients with hypertrophic cardiomyopathy: Comparison with 123I-β-methyl iodophenyl pentadecanoic acid myocardial scintigraphy.

Tissue Doppler imaging (TDI) has been utilized to evaluate left ventricular myocardial dysfunction in patients with hypertrophic cardiomyopathy (HCM); however, no clear explanation for the abnormality of TDI variables has been forthcoming. Peak negative myocardial velocity gradient (MVG) derived from TDI may correlate with a disorder of fatty acid metabolism in patients with HCM. Tissue Doppler imaging and 123I-beta-methyl iodophenyl pentadecanoic acid (123I-BMIPP) myocardial scintigraphy were performed in 15 patients with asymmetric septal hypertrophy (mean age 47 +/- 18 years) and in 12 healthy controls (mean age 43 +/- 10 years). In early 123I-BMIPP images, accumulation defects were observed in the ventricular septum in 12 patients and in the posterior wall in 8 patients with HCM. Peak negative MVG in the ventricular septum (1.1 +/- 0.5 vs. 2.8 +/- 0.5, p < 0.0001) and posterior wall (5.2 +/- 1.4 vs. 6.7 +/- 0.8, p < 0.01 ) was significantly lower in the HCM group than in the controls; also, these parameters were significantly lower in patients with than in those without a defect in the region in question. The peak negative MVG in the ventricular septum and posterior wall correlated inversely with the washout rate in all subjects. Peak negative MVG according to TDI is related to disorder of fatty acid metabolism in the regional left ventricular myocardium of patients with HCM.


Determinants of left ventlicular diastolic function during atrial fibrillation: Beat-by-beat analysis in acute dog experiments.

Left ventricular (LV) diastolic function during atrial fibrillation (AF) remains poorly understood due to the complex interaction of factors and beat-to-beat variability. The purpose of the present study was to elucidate the physiological determinants of beat-to-beat changes in LV diastolic function during AF. The RR intervals preceding a given cardiac beat were measured from the right ventricular electrogram in 12 healthy open-chest mongrel dogs during AF. Doppler echocardiography and LV pressure and volume beat-to-beat analyses were performed. The LV filling time (FT) and early diastolic mitral inflow velocity-time integral (E(vti)) were measured using the pulsed Doppler method. The LV end-diastolic volume (EDV), peak systolic LV pressure (LVP), minimum value of the first derivative of LV pressure curve (dP/dt(min)), and the time constant of LV pressure decay (tau) were evaluated with the use of a conductance catheter for 100 consecutive cardiac cycles. Beat-to-beat analysis revealed a cascade of important causal relations. LV-FT showed a significant positive linear relationship with E(vti) (r = 0.87). Importantly, there was a significant positive linear relationship between the RR interval and LV-EDV in the same cardiac beat (r = 0.53). Consequently, there was a positive linear relationship between LV-EDV and subsequent peak systolic LVP (r = 0.82). Furthermore, there were significant positive linear and negative curvilinear relationships between peak systolic LVP and dP/dt(min) (r = 0.95) and tau (r = -0.85), respectively, in the same cardiac beat. In addition, there was a significant negative curvilinear relationship between dP/dt(min) and tau (r = -0.86). We have concluded that the determinants of LV diastolic function in individual beats during AF depend strongly on the peak systolic LVP. This suggests that the major benefit of slower ventricular rate appears related to lengthening of LV filling interval, promoting subsequent higher peak systolic LVP and greater LV relaxation.


The Effects of Coupled Pacing on Cardiac Performance during Acute Atrial Tachycardia and Fibrillation --- An Old Therapy Revisited for a New Reason

Atrial tachycardia (AT) and fibrillation (AF) result in rapid ventricular rates that are detrimental to optimal cardiac function. The purpose of this study was to determine whether the application of a coupled pacing (CP) regimen would improve ventricular function by decreasing the ventricular rate of mechanical contractions (VRMCs). We simulated AT by pacing either atrium at a rate that resulted in a rapid but regular ventricular rate in seven anesthetized dogs. AF was induced by increasing the atrial pacing rate until atrial activation did not follow the pacing. After the induction of either AT or AF, we applied CP after each intrinsic ventricular activation. We measured the VRMCs and left ventricular (LV) pressures and volumes via a pressure-conductance catheter. The marked reductions in VRMCs during CP resulted in increases in LV end-diastolic volume. The CP resulted in virtually no mechanical contractions, whereas the strength of contractions from the normal electrical activation increased. The increases in the positive LV rate of pressure development over time and LV ejection fraction during CP were the result of postextrasystolic potentiation. The average stroke work (area of the pressure-volume loops) increased as a result of CP during both AT and AF. Despite the large increases in stroke volume (approximately 2x) during CP, the changes in cardiac output were moderate because the VRMCs markedly decreased (approximately 1/2). We conclude that CP therapy may be a viable therapy for slowing the heart rate and improving cardiac performance in patients with AT and AF.

American Journal of Physiology, Heart and Circulatory Physiology


Phased-Array Intracardiac Echocardiography Monitoring During Pulmonary Vein Isolation in Patients With Atrial Fibrillation. --- Impact on Outcome and Complications.

The objective of this study was to assess the impact of intracardiac echocardiography (ICE) on the long-term success and complications in patients undergoing pulmonary vein isolation (PVI) for treatment of atrial fibrillation (AF). Three hundred fifteen patients underwent PVI for treatment of AF. Each patient underwent ostial isolation of all PVs using a cooled-tip ablation catheter. PVI was performed using circular mapping (CM) alone (group 1, 56 patients), CM and ICE (group 2, 107 patients), and CM and ICE with titration of radiofrequency energy based on visualization of microbubbles by ICE (group 3, 152 patients). After a mean follow-up time of 417+/-145 days, 19.6% (11 of 56), 16.8% (18 of 107), and 9.8% (15 of 152) of patients in groups 1, 2, and 3 experienced recurrence of AF, respectively. Moreover, whereas no group 3 patient experienced severe (>70%) PV stenosis, severe PV stenosis was documented in 3 (3.5%) of 56 patients in group 1 and in 2 (1.8%) of 107 patients in group 2 (P<0.05). No embolic events were detected in group 3 patients. Intracardiac echocardiography improves the outcome of cooled-tip PVI. Power adjustment guided by direct visualization of microbubble formation reduces the risk of PV stenosis and improves long-term cure.


Novel approach to the quantitation of regional left ventricular systolic and diastolic function using tissue Doppler imaging to create a myocardial velocity profile and gradient

The myocardial velocity profile (MVP) and gradient (MVG) between the endocardium and epicardium of the left ventricular (LV) wall measured by color-coded tissue Doppler imaging (TDI) are new indices for evaluating regional LV myocardial function. However, accurate recording and measurement of the MVP is difficult using conventional methodology because of the stochastic nature of the ultrasound signal; that is, the effect of speckled noise. The aim of this study was to validate the accuracy and establish the validity of a newly developed method for measuring the MVP and MVG using 10 clinically normal controls and 10 patients with a hypertensive hypertrophied LV posterior wall. A non-isotropic, averaging algorithm was developed that was capable of obtaining a stable MVP (averaged MVP). Averaged MVP was recorded using parasternal, LV short-axis, color-coded TDI, placing regions of interest along the LV posterior wall with the reference point for angle-correction being at the center of LV contraction. The velocity from epicardium to endocardium within the region of interest was automatically angle-corrected to calculate the velocity component radially relative to the LV cavity and was spatially averaged along the circumference within the region of interest. Inter- and intraobserber variabilities of measurements were lower in the averaged MVP and MVG than in the conventional MVP and MVG. The correlation coefficients of the linear regression lines of systolic and early diastolic MVPs in the LV posterior wall were higher in all controls and hypertensive patients with the averaged method than with the conventional TDI procedures. The mean peak systolic and early diastolic MVGs were lower in the hypertensive group than in the controls. In conclusion, the newly developed averaged MVP provides a stable and reproducible index for the quantitative assessment of regional LV myocardial function.


Prognostic value of the atrial systolic mitral annular motion velocity in patients with left ventricular systolic dysfunction.

Transmitral flow velocity variables are powerful predictors of poor prognosis in patients with left ventricular (LV) systolic dysfunction. However, these variables may not accurately reflect the severity of pulmonary congestion. This study was designed to determine whether the peak atrial systolic mitral annular motion velocity (MA-Aw) measured by pulsed Doppler tissue imaging can predict cardiac death or hospitalization for worsening heart failure in patients with LV systolic dysfunction. MA-Aw was recorded in 96 patients with LV systolic dysfunction who were followed up for 29 +/- 10 months. All patients underwent Doppler echocardiography on entry into the study, and cardiac catheterization was performed in 45 patients. Patients were divided into 3 groups on the basis of the ratio of early (E) to late (A) diastolic filling (E/A) of the transmitral flow velocity: group 1 (n=31; E/A < 1); group 2 (n=37; 1 < or = E/A < 2); and group 3 (n=28; E/A > or = 2). During follow-up, 36 patients (38%) died of cardiac causes and 34 (35%) were hospitalized for worsening heart failure. There were 2 cardiac deaths (6%) in group 1, 14 (39%) in group 2, and 20 (56%) in group 3. The MA-Aw correlated closely with the mean pulmonary capillary wedge pressure. Univariate Cox model analysis showed that MA-Aw < or = 5 cm/s was the most powerful predictor of cardiac death or hospitalization for worsening heart failure compared with clinical, hemodynamic, and the other echocardiographic variables. Furthermore, MA-Aw < or = 5 cm/s was clearly discernible as a good predictor of cardiac mortality on multivariate Cox model and as assessed by Kaplan-Meier method. The MA-Aw obtained by pulsed Doppler tissue imaging is a sensitive index of pulmonary congestion in patients with LV systolic dysfunction. It is a simple and noninvasive outcome measure and can be used to monitor treatment.

Journal of the American Society of Echocardiography


Prevalence of left ventricular diastolic dysfunction by Doppler echocardiography: Clinical application of the Canadian consensus guidelines.

We evaluated diastolic filling patterns using Doppler echocardiography in 520 consecutive patients referred to our laboratory for transthoracic echocardiograms retrospectively and applied the standard guidelines used to characterize left ventricular (LV) diastolic function. Patients were classified by the Canadian consensus guidelines using transmitral and pulmonary venous Doppler echocardiographic parameters to have normal diastolic function or mild (abnormal relaxation), mild-to-moderate, moderate (pseudonormal), or severe (restrictive) diastolic dysfunction. LV diastolic dysfunction was present in 290 (56%) patients, whereas 167 (45%) patients with a normal LV ejection fraction had abnormal diastolic function. Patients with progressively more abnormal diastolic patterns had greater structural abnormalities with larger left atrial and LV size and lower LV ejection fractions. In the subset of patients with clinical evidence of congestive heart failure (99 patients), the prevalence of primary diastolic heart failure was 38% and most patients had underlying coronary or hypertensive heart disease. Standard guidelines of Doppler echocardiographic parameters allow semiquantitation of diastolic function and can be applied to studying large number of patients in a large clinical practice.

Journal of the American Society of Echocardiography


The role of short- and long-axis function in determining late diastolic left ventricular filling in patients with hypertension: Assessment by pulsed Doppler tissue imaging.

Left ventricular (LV) wall motion velocity during atrial systole is mediated by both transmitral flow and LV myocardial compliance at end-diastole. LV wall distensibility along the long- and short-axis during atrial systole and late diastolic LV filling may vary according to the remodeling of LV morphology. We measured LV wall motion velocities along the long and short axes using pulsed Doppler tissue imaging in 127 patients with hypertension to evaluate the relationship between the hemodynamic changes and LV morphology and to determine the role of both long- and short-axis function in late diastolic LV filling. Participants were classified into 3 groups according to LV dimension and end-diastolic wall thickness determined by M-mode echocardiography: group A (n = 62) without LV dilation or hypertrophy, group B (n = 55) with LV hypertrophy, and group C (n = 10) with LV dilation and systolic dysfunction. The time constant of the LV pressure decay during isovolumic diastole and the LV end-diastolic pressure were longest and greatest, respectively, in group C, compared with groups B and A. There were no significant differences in active left atrial emptying volume during atrial contraction determined by computerized echocardiographic 3-dimensional reconstruction among patient and control groups. The peak atrial systolic motion velocity of the LV posterior wall along the long axis was significantly lower in groups B and C, particularly in the latter group, than in group A. The peak atrial systolic motion velocity of the LV posterior wall along the short axis was greatest in group B and was lowest in group C compared with the other groups, respectively. The peak atrial systolic motion velocity of the LV posterior wall was greater along the long axis than the short axis in group A, but was less than the short axis in group B. In conclusion, the long- and short-axis function of the LV wall during atrial systole varies in patients with hypertension according to the severity of hemodynamic and morphologic abnormalities. The degree of LV wall expansion along the short axis is an important factor resulting from the atrial kick, and a determinant of its effectiveness.


Early systolic mitral annular motion velocities responses to dobutamine infusion predict myocardial viability in patients with previous myocardial infarction.

This study was undertaken for the determination of the correlation between myocardial viability and regional systolic mitral annular motion velocity (MAV) response to dobutamine stress in patients with previous myocardial infarction (MI) with pulsed tissue Doppler scan imaging. The study included 45 patients (mean age, 65 +/- 12 years) with previous MI with 1 major coronary lesion and 30 healthy individuals (mean age, 61 +/- 14 years). 99mTc-methoxyisobutylisonitrile scintigraphy was performed to divide the patients into 2 groups: the viability (+) group (n = 25) and the viability (-) group (n = 20). Dobutamine was infused (at 2, 5, 10, and 20 microg/kg/min), and the peak first and second systolic MAVs (Sw1 and Sw2, respectively) were measured at the level of the mitral annulus corresponding to the infarct regions in the MI group and to the 6 mitral annular sites in the control group. In addition, the left ventricular wall motion score index (WMSI) was determined with 2-dimensional echocardiography. At baseline, the WMSI was significantly greater and the mean Sw1 and Sw2 were significantly lower in both the viability (+) and (-) groups than in the control group, but there were no significant differences between the viability (+) and (-) groups. After dobutamine infusion, the WMSI improved only in the viability (+) group. The mean Sw1 and Sw2 increased significantly with 2 microg/kg/min and 5 microg/kg/min of dobutamine, respectively, in the viability (+) group. With an increase in Sw1 of 2.0 cm/s or more with 5 microg/kg/min of dobutamine, viable myocardium was detected, with a sensitivity of 92% and a specificity of 90%. There were no significant increases in Sw1 or Sw2 in the viability (-) group with dobutamine infusion. Viable left ventricular myocardium is identified with peak early systolic MAV during dobutamine infusion.


Effect of cilnidipine on left ventricular diastolic function in hypertensive patients as assessed by pulsed Doppler echocardiography and pulsed tissue Doppler imaging.

The purpose of the present study was to examine the mechanisms of improvement in left ventricular (LV) diastolic function in hypertensive patients treated with cilnidipine, a new and unique calcium antagonist that has both L-type and N-type voltage-dependent calcium channel blocking actions, using pulsed Doppler echocardiography and pulsed tissue Doppler imaging. The study comprised 35 untreated patients with essential hypertension (19 men and 16 women; mean age 65+/-10 years). The peak early diastolic and atrial systolic transmitral flow velocities (E and A, respectively) and their ratio (E/A), and the peak early diastolic and atrial systolic motion velocities (Ew and Aw, respectively) of the LV posterior wall and their ratio (Ew/Aw) were determined in all patients before and after 1, 3 and 6 months on cilnidipine (10 mg/day). One month: Systolic and diastolic blood pressures were significantly decreased. E and E/A were significantly increased, whereas there were no significant changes in Ew and Ew/Aw. Three months: Ew and Ew/Aw were significantly increased compared to those before and 1 month after cilnidipine. Six months: E and E/A were significantly increased compared with before and 3 months after cilnidipine, and Ew and Ew/Aw were significantly increased compared with before cilnidipine. Moreover, the LV mass index was significantly decreased compared to that before cilnidipine. In summary, changes in LV diastolic performance in patients with essential hypertension following cilnidipine treatment were biphasic with an initial increase in early diastolic transmitral flow velocity and a later increase in early diastolic LV wall motion velocity. The initial and later changes can be related to an acute change in afterload and a later improvement in LV relaxation.


Use of angiotensin II stress pulsed tissue Doppler imaging to evaluate regional left ventricular contractility in patients with hypertrophic cardiomyopathy.

There is controversy concerning whether contract-ility in the nonhypertrophied region of the left ventricular (LV) wall is impaired or normal in patients with hypertrophic cardiomyopathy (HCM). Global LV systolic function decreases with increases in afterload in this disease. This study was performed to identify abnormalities in regional LV contractility along the long and short axes in the setting of HCM with the use of angiotensin II (AT-II) stress pulsed tissue Doppler imaging (PTDI). Angiotensin II was administered intravenously to patients with asymmetric septal hypertrophy (HCM group, n = 21) and age-matched normal volunteers (N group, n = 12). We then measured the percent LV fractional shortening (%FS) and end-systolic circumferential LV wall stress by M-mode echocardiography, LV ejection fraction (LVEF) by 2-dimensional echocardiography, and time-velocity integral (TVI) of LV outflow velocity by pulsed Doppler echocardiography. The peak first and second systolic LV wall motion velocities along the long (L-Sw(1) and L-Sw(2)) and short (S-Sw(1) and S-Sw(2)) axes were measured in the LV posterior wall and ventricular septum with the use of PTDI. The end-systolic circumferential LV wall stress at baseline was significantly lower in the HCM group. The L-Sw(1) and L-Sw(2) for the posterior wall were significantly lower in the HCM group, but the S-Sw(1) and S-Sw(2) for the posterior wall and ventricular septum were similar in the two groups. The %FS, LVEF, TVI, and systolic PTDI variables along both axes for the posterior wall decreased significantly, and end-systolic circumferential LV wall stress increased significantly at AT-II doses of 0.005 or 0.010 microg/kg per minute in the HCM group. No significant changes were found in either group in the systolic PTDI variables (except for L-Sw(1)) for the ventricular septum with AT-II infusion. Contractility along the long and short axes of the nonhypertrophied LV wall is easily impaired with increases in afterload in patients with HCM, resulting in a decrease in global LV systolic function. We found AT-II stress PTDI to be a safe and useful technique for evaluating the regional LV systolic function in this disease.


Hepatopulmonary syndrome-discussion of cardiopulmonary parameters

We report a 70-year-old man with hepatopulmonary syndrome (HPS) in C liver cirrhosis. Hypoxemia worsened markedly, especially on exertion, while the hepatic function was clinically stable. Contrast echocardiography, 99mTc macroaggregated albumin (99mTcMAA) lung scan, and pulmonary angiography were performed. The findings suggested the presence of both intrapulmonary vascular dilatation and substantial right-to-left shunt. The contribution of intrapulmonary vascular abnormalities in patients with severe liver cirrhosis without abnormal chest radiography and spirometry tests when marked hypoxemia is present should be investigated.

The Journal of Medical Investigation : JMI


Relationship between left atrial appendage function and plasma concentration of atrial natriuretic peptide.

It has been reported that the most intensely granuled cardiocytes secreting atrial natriuretic peptide (ANP) are located in the atrial appendages. To evaluate the mechanisms of ANP release in congestive heart failure. The relationship between ANP and left atrial appendage (LAA) function was evaluated in 36 patients who underwent both transoesophageal echocardiography and cardiac catheterization. ANP level correlated positively with mean pulmonary capillary wedge pressure (mPCWP; r=0.75, P<0.0001), whereas it showed no significant correlation with the mean right atrial pressure. mPCWP correlated positively with the maximal LAA area (LAAa; r=0.79, P<0.0001) and negatively with the LAA ejection fraction during atrial contraction (LAA-EF; r=-0.61, P<0.0001) and peak late diastolic LAA emptying flow velocity (LAAF; r=-0.69, P<0.0001). ANP level correlated negatively with the LAA-EF (r=-0.56, P<0.001) and with LAAF (r=-0.61, P<0.0001). ANP level correlated more closely with the LAAa (r=0.79, P<0.0001) than with maximal LA volume (r=0.34, P<0.05). Multiple stepwise regression analysis selected LAAa as the only factor independently related to the plasma concentration of ANP (ANP=-22.4+28.6 LAAa, r=0.79, P<0.0001). We conclude that the factor most predictive for ANP in patients with left-sided cardiac dysfunction is distension of the LAA wall rather than elevation in the LA pressure or distension of the body of LA. This is consistent with the known distribution of ANP-secreting cardiocytes.


Detection of left ventricular regional relaxation abnormalities and asynchrony in patients with hypertrophic cardiomyopathy with the use of tissue Doppler imaging.

It is well known that the distribution and magnitude of left ventricular (LV) hypertrophy are not uniform in patients with hypertrophic cardiomyopathy (HCM), which results in regional heterogeneity of LV early diastolic function. The advent of tissue Doppler imaging (TDI) has allowed the noninvasive evaluation of regional LV wall motion velocities. The aim of this study was to evaluate regional LV relaxation abnormalities and asynchrony noninvasively in patients with HCM by using pulsed and color-coded TDI. We studied 20 patients with asymmetric septal hypertrophy (HCM group) and 18 age-matched normal patients (control group). The peak early diastolic motion velocity (Ew) and time from the aortic component of the second heart sound to the peak of the Ew (II(A)-Ew) were measured by pulsed TDI. The myocardial velocity gradient during early diastole (MVG-Ew) also was measured by color-coded TDI. Mean values for these parameters were determined on the basis of measurements made at 2 sites of the ventricular septum or posterior wall at the levels of chordae tendineae and papillary muscles. The mean Ew and mean MVG-Ew for the ventricular septum and posterior wall were significantly lower, and mean II(A)-Ew was significantly prolonged in the HCM group compared with the control group. This difference was most pronounced in the hypertrophied ventricular septum of the HCM group. The standard deviations of II(A)-Ew for the ventricular septum and posterior wall were significantly greater in the HCM group than in the control group. The time constant of LV pressure decay during isovolumic diastole (tau) correlated inversely with Ew and MVG-Ew and correlated directly with II(A)-Ew. Furthermore, tau correlated directly with the standard deviation of the II(A)-Ew. LV early diastolic function in patients with HCM may be mediated by an augmentation of regional LV relaxation abnormalities and asynchrony.


Subendocardial motion in hypertrophic cardiomyopathy: assessment from long and short axis views by pulsed tissue Doppler imaging.

Tissue Doppler imaging (TDI) is a recently developed technique that allows the instantaneous measurement of intrinsic regional myocardial motion velocity. Pulsed TDI is capable of separately assessing left ventricular (LV) regional motion velocity caused by circumferential and longitudinal fiber contraction. This particular feature of function is still controversial in patients with hypertrophic cardiomyopathy (HC). To better characterize intrinsic circumferential and longitudinal LV systolic myocardial function in HC, we used pulsed TDI to measure short- and long-axis LV motion velocities, respectively. The subendocardial motion velocity patterns at the middle of the LV posterior wall (PW) and ventricular septum (IVS) in LV parasternal and apical long-axis views were recorded by pulsed TDI in 19 patients with nonobstructive HC and in 21 normal controls (NC). Peak short- and long-axis systolic subendocardial velocities in both the LV PW and IVS were significantly smaller in the HC group than in the NC group, and the time to peak velocity was significantly delayed. Furthermore, peak PW systolic velocity was significantly greater along the long axis than along the short axis in the NC group (8.8 +/- 1.5 cm/s vs 8.2 +/- 1.4 cm/s, P <.05), whereas the opposite was observed in the HC group (6.1 +/- 1.2 cm/s vs 7.5 +/- 1.0 cm/s, P <.0001). No significant differences were found in either group between the long- and short-axis IVS velocities (HC: 5.9 +/- 1.4 cm/s vs 5.5 +/- 1.3 cm/s; NC: 7.8 +/- 1.3 cm/s vs 7.9 +/- 1.6 cm/s). By using the capability of pulsed TDI for the evaluation of intrinsic myocardial velocity instantaneously in a specific region and direction, we found impairment of LV myocardial systolic function in patients with HC not only in the hypertrophied IVS but also in the nonhypertrophied LV PW. We also found a greater decrease in LV PW velocities along the long axis than the short axis, suggesting greater impairment of long-axis contraction in patients with HC. Because our HC patients did not appear to have excessive intracavitary pressure, these results suggest that the relatively normal-appearing PW is directly affected by the HC pathologic process.

Journal of the American Society of Echocardiography


心エコー・ドプラ法による左室拡張機能評価からみた心不全-治療効果と予後-

心エコー・ドプラ法による左室拡張機能評価からみた心不全-治療効果と予後-


Evaluation of left ventricular contraction abnormalities in patients with dilated cardiomyopathy with the use of pulsed tissue doppler imaging


Influence of aging on systolic left ventricular wall motion velocities along the long and short axes in clinically normal patients determined by pulsed tissue Doppler imaging.


Effect of aging on diastolic left ventricular myocardial velocities measured by pulsed tissue Doppler imaging in healthy subjects.


Effect of an acute increase in afterload on left ventricular regional wall motion velocity in healthy subjects.


Pulsed tissue Doppler imaging of left ventricular systolic and diastolic motion velocities to evaluate differences between long and short axes in healthy subjects.


Assessment of temporal relationship between left ventricular relaxation and filling during the early diastole with pulsed Doppler echocardiography and tissue Doppler imaging.


Left ventricular systolic wall motion velocities along the long and short axis measured by pulsed tissue Doppler imaging in patients with atrial fibrillation.


Evaluation of the hemodynamic relationship between the left atrium and left ventricle during atrial systole by pulsed tissue Doppler imaging in patients with left heart failure.


Regional left ventricular myocardial contraction abnormalities and asynchrony in patients with hypertrophic cardiomyopathy evaluated by magnetic resonance spatial modulation of magnetization myocardial tagging.


Assessment of the systolic left ventricular myocardial velocity profile and gradient using tissue Doppler imaging in patients with hypertrophic cardiomyopathy.


Left ventricular diastolic properties of hypertensive patients measured by pulsed tissue Doppler imaging.


Assessment of abnormal left atrial relaxation by transesophageal pulsed Doppler echocardiography of pulmonary venous flow velocity.


Right heart flow dynamics after tricuspid valve annuloplasty. Characteristics and time course

To evaluate the effect of tricuspid annuloplasty (TAP) on right heart flow dynamics, we analyzed tricuspid inflow velocity pattern, jugular venous pulse and color Doppler flow signal of tricuspid regurgitation (TR) before and after surgery in 16 patients who underwent TAP (TAP group). Cardiac rhythm was atrial fibrillation in all patients. Twelve patients with lone atrial fibrillation served as controls (AF group). Patients in the TAP group were studied before and serially after surgery with a mean follow-up period of 2.7 years. TAP was performed according to the modified De Vega technique in all patients. In a comparison of the most recent data in the TAP group and the data in the AF group, the maximum tricuspid inflow velocity was significantly increased, and both the deceleration time of the tricuspid inflow velocity wave and the y-h interval of the jugular venous pulse were significantly prolonged in the TAP group compared to the AF group. Immediately after surgery, in the TAP group, the area of the TR jet was markedly decreased, and the deceleration time of the tricuspid inflow velocity wave was significantly prolonged compared to those before surgery. The area of the TR jet was dramatically decreased and remained small during the follow-up period. Thus, TAP may produce mild tricuspid stenosis but may also confer sustained preventive effects against TR.


Assessment of left ventricular systolic wall motion velocity using pulsed tissue Doppler imaging: comparison with peak dP/dt of the left ventricular pressure curve.


Evaluation of left atrial filling using systolic pulmonary venous flow velocity measurements in patients with atrial fibrillation.


Right and left ventricular wall motion velocities as diagnostic indicators of constrictive pericarditis.


Role of left atrial appendage in left atrial reservoir function as evaluated by left atrial appendage clamping during cardiac surgery.


Differences in transmitral flow velocity pattern during increase in preload in patients with abnormal left ventricular relaxation.

Changes in transmitral flow (TMF) and pulmonary venous flow (PVF) velocities during increases in preload were compared in patients with a higher peak atrial systolic velocity than peak early diastolic velocity (A/E > 1) for the TMF velocity to determine differences in hemodynamic response. Fifteen patients with dilated hearts, 22 with hypertrophied hearts and 15 control patients were studied. TMF and PVF velocities were recorded by transesophageal pulsed Doppler echocardiography before and during application of lower body positive pressure. The value for peak early diastolic velocity increased, while the isovolumic relaxation time decreased with increases in preload in all groups. The value for peak atrial systolic velocity decreased in the dilated-heart group, but increased in the hypertrophied-heart and control groups. The peak second systolic and early diastolic PVF velocities increased in the dilated- and hypertrophied-heart groups, but did not change in the control group. The peak atrial systolic PVF velocity and the difference in duration of the atrial systolic PVF and TMF velocities increased in the dilated- and hypertrophied-heart groups, and its changing rate was highest in the group with dilated hearts. These results suggest that both peak early diastolic and atrial systolic TMF velocities increase during increases in preload through the Frank-Starling mechanism in hypertrophied hearts. Furthermore, the left ventricular functional reserve was lower in the dilated-heart group. Thus, TMF and PVF velocities respond differently during increases in preload, depending on the underlying heart disease.


Characteristics of Coronary Flow Velocity in Constrictive Pericarditis

Catheterization and Cardiovascular Diagnosis


Transesophageal pulsed Doppler echocardiographic study of systolic flow velocity patterns of the pulmonary vein in patients with atrial fibrillation.


Difference in systolic motion velocity of the left ventricular posterior wall in patients with asymmetric septal hypertrophy and prior anteroseptal myocardial infarction: evaluation by pulsed tissue Doppler imaging.


Left atrial contribution to left ventricular filling in patients with mitral stenosis: combined analysis of transmitral and pulmonary venous flow velocities.


Echocardiographic characteristics and causal mechanism of physiologic mitral regurgitation in young normal subjects.


Clinical application of pulsed Doppler tissue imaging for assessing abnormal left ventricular relaxation.


単冠動脈症を合併した肥大型心筋症の1例

単冠動脈症を合併した肥大型心筋症の1例


Evaluation of left atrial appendage function by measurement of changes in flow velocity patterns after electrical cardioversion in patients with isolated atrial fibrillation


Tricuspid inflow and regurgitant flow dynamics after mitral valve replacement: Differences relating to surgical repair of the tricuspid valve

Changes in tricuspid inflow and regurgitant flow dynamics were evaluated in patients with functional tricuspid regurgitation (TR) who underwent mitral valve replacement (MVR) with and without tricuspid annuloplasty (TAP). In a group of 30 patients, all with atrial fibrillation, 15 underwent TAP performed according to the modified De Vega technique; the remaining 15 did not undergo TAP. Patients were studied before and serially after surgery, using pulsed and color Doppler echocardiography. The mean follow up was 4.7 years in the TAP group and 5.1 years in the non-TAP group. In the TAP group, immediately after surgery, the area of the TR jet decreased markedly, and the deceleration time of the tricuspid inflow velocity wave was significantly prolonged compared with that before surgery. By contrast, in the non-TAP group, both the area of the TR jet and deceleration time of tricuspid inflow velocity were virtually unchanged. The area of the TR jet remained small for a long period in the TAP group, but in non-TAP patients was increased in four cases over seven years, with two patients developing right-sided heart failure. Recent data showed the area of the TR jet to be significantly smaller, with maximum tricuspid inflow velocity significantly increased, and deceleration time of the tricuspid inflow velocity wave significantly prolonged in the TAP group compared with the non-TAP group. In patients with functional tricuspid regurgitation undergoing MVR, concomitant TAP may cause mild tricuspid stenosis, but produces sustained preventive effects against TR. Careful follow up is needed in patients who have not undergone TAP, as TR is not markedly decreased and may even be exacerbated. Aggressive TAP is recommended in patients showing dilatation of the tricuspid annulus, even if TR is mild.


Cross sectional echocardiographic demonstration of the mechanisms of abnormal interventricular septal motion in congenital total absence of the left pericardium.


Transesophageal pulsed Doppler echocardiographic evaluation of left atrial systolic performance in hypertrophic cardiomyopathy: combined analysis of transmitral and pulmonary venous flow velocities.


Evaluation of cardiac function by pulsed and continuous Doppler echocardiography and tissue Doppler imaging


Transesophageal echocardiographic prediction of initially successful electrical cardioversion of isolated atrial fibrillation. --- Effects of left atrial appendage function.


The 'Sail sound' and tricuspid regulation in Epstein's anomaly: the value of echocardiography in evaluating their mechanisms.


Tricuspid inflow and regurgitant flow dynamics after mitral valve replacement: differences relating to surgical repair of the tricuspid valve.


Concealed left ventricular hypertrophy and diastolic dysfunction in hypertrophic cardiomyopathy in the presence of acute left ventricular volume overload: a case report.


Left atrial systolic performance in the presence of elevated left ventricular end-diastolic pressure: evaluation by transesophageal pulsed Doppler echocardiography of left ventricular inflow and pulmonary venous flow velocities.


Relationship between the angiotensin converting enzyme gene polymorphism and the effects of Enalapril on left ventricular hypertrophy and impaired diastolic filling in essential hypertension: M-mode and pulsed Doppler echocardiographic studies.

To investigate the relationship between the angiotensin converting enzyme (ACE) gene polymorphism and the effects of the ACE inhibitor enalapril on left ventricular hypertrophy and impaired diastolic filling. Enalapril (5-10 mg/day) was administered for 12 months to 60 previously untreated patients with essential hypertension. M-mode and pulsed Doppler echocardiography were performed before and after treatment, and changes in various parameters after treatment with enalapril were examined. ACE gene polymorphism was examined by the polymerase chain reaction method and the patients were classified as having the 190 bp deletion homozygous (DD) genotype, the 490 bp insertion homozygous (II) genotype or the 490 bp insertion 190 bp deletion heterozygous (ID) genotype. The DD genotype was observed in 10 patients (17%), the ID genotype in 24 patients (40%) and the II genotype in 26 patients (43%). Plasma ACE activity before treatment with enalapril was significantly higher in seven patients with DD genotype than it was in 18 patients with ID genotype and in 14 patients with II genotype. In all of the 60 patients, the left ventricular mass index, the peak atrial systolic velocity:early diastolic velocity ratio and the deceleration time from the peak of the early diastolic wave to the baseline in transmitral flow velocity were decreased significantly after treatment with enalapril. The changes in left ventricular mass index and atrial systolic velocity:early diastolic velocity ratio after enalapril administration were significantly greater in the DD genotype group than they were in the other two genotype groups. Enalapril-induced regression of left ventricular hypertrophy and improvement in left ventricular impaired diastolic filling were significantly greater in the DD genotype group than they were in the ID and II genotype groups, suggesting that the circulating and tissue renin-angiotensin systems, particularly the former system, are most active in hypertensive patients with the DD genotype.


Influence of left atrial pressure on left atrial appendage flow velocity patterns in patients in sinus rhythm.

Journal of the American Society of Echocardiography


The efficacy of inhaled nitic oxide in a patient with acute massive pulmonary thromboembolism.

Journal of the Japanese Society of Intensive Care Medicine


Influence of aging on left atrial appendage flow velocity patterns in normal subjects.


Changes in left ventricular inflow and pulmonary venous flow velocities during preload alteration on hypertrophic cardiomyopathy.


Changes in transmitral and pulmonary venous flow velocity patterns after cardioversion of atrial fibrillation.


一酸化窒素吸入療法が有効であった急性広汎型血栓塞栓症の1例

一酸化窒素吸入療法が有効であった急性広汎型血栓塞栓症の1例


右心内転移をきたした悪性黒色腫の1例

右心内転移をきたした悪性黒色腫の1例


Malignant melanoma metastasizing to the right heart: a case report.


A Case of Cardiac Amyloidosis Presenting with Mid- to Late Diastolic Retrograde Flow from the Left Atrium to the Pulmonary Vein: Transesophageal Pulsed Doppler Echocardiographic Observations.


Clinical significance of the apical late systolic ejection murmur: a new phonocardiographic sign indicating dynamic mid-left ventricular obstruction.


Systolic and diastolic mitral regurgitation in a patient with annulo-aortic ectasia demonstrated by color Doppler flow imaging.


Peculiar patterns of aortic regurgitation and carotid pulse due to dysfunction of a Medtronic Hall prosthetic valve: a case report.


Possible mechanisms of mitral regurgitation in dilated hearts: a study using transesophageal echocardiography.


Assessment of left atrial pressure and volume changes during atrial systole with transesophageal pulsed Doppler echocardiography of transmitral and pulmonary venous flow velocities.


Predisposing factors of severe mitral regurgitation in idiopathic mitral valve prolapse.


Pulmonary and systemic venous flow patterns assessed by transesophageal Doppler echocardiography in congenital absence of the pericardium.


Changes in pulmonary venous and transmitral flow velocity patterns after cardioversion of atrial fibrillation


拡大心における僧帽弁逆流の出現機序 --- 経食道心エコー図法による検討

拡大心における僧帽弁逆流の出現機序 --- 経食道心エコー図法による検討


特発性僧帽弁逸脱における重症僧帽弁逆流の出現要因について

特発性僧帽弁逸脱における重症僧帽弁逆流の出現要因について


心房細動例における除細動前後の肺静脈および僧帽弁口血流速波形変化

心房細動例における除細動前後の肺静脈および僧帽弁口血流速波形変化


Evaluation of left ventricular diastolic hemodynamics from the left ventricular inflow and pulmonary venous flow velocities in hypertrophic cardiomyopathy.


Mechanism of mitral regurgitation in dilated hearts: transesophageal echocardiographic study.


The first heart sound in atrial septal defect with reference to atrioventricular valve motion and hemodynamics.


Histopathologic studies of innervation of normal and prolapsed mitral valves of humans.


Critical Limb Threatening Ischemia Due to Severe Polyarteritis Nodosa-A Case Report

A delayed diagnosis of polyarteritis nodosa may lead to critical limb-threatening ischemia (CLTI). A 74-year-old woman presented with left-foot pain and was treated with oral vasodilators and antiplatelet agents. However, the distal ischemia progressed to CLTI, including gangrene of the fingers and toes, and bilateral foot dropping appeared because of peroneal nerve paralysis. Angiography of the extremities revealed obstruction and stenosis of medium-sized arteries. Based on the progressive distal gangrene, mononeuropathy multiplex, and pathological findings of necrotic vasculitis, polyarteritis nodosa was diagnosed, and the patient's condition improved. A biopsy and neurological examination are essential for the appropriate diagnosis of PAN and immediate treatment.


心電図セミナー(306)

心電図セミナー(306)


心電図セミナー(304)

心電図セミナー(304)


Elevated Concentration of Interferon-Inducible Protein of 10kd (IP-10) is Associated with Coronary Atherosclerosis.


Predictors of Local Hypercoagulability after Sirolimus-Eluting Stent Implantation: Implication for Correlates of Late Stent Thrombosis.


Elevated Concentration of Pentraxin 3 is Associated with Coronary Plaque Vulnerability.


Ghrelin Attenuates Myocardial Ischemia/Reperfusion Injury via the Extracellular Signal-Regulated Kinase 1/2 and Phosphatidylinositol.


Long-Term Local Inflammatory Response after Coronary Artery Stenting with Drug-Eluting Stent.


Left Atrial Volume does not reflect Brain Natriuretic Peptide Levels in Patients with Atrial Fibrillation.


Importance of Left Atrial Function for the Pseudonormalization of Transmitral Flow Velocity Pattern in Patients with Hypertrophic Cardiomyopathy.


E/e' as a Predictor of the Cardiac Response to Increment of Preload in Patients with Atrial Fibrillation.


Long-term endothelial dysfunction after coronary artery stenting with drug-eluting stent associated with local inflammatory response.


Local hypercoagulability and endothelial dysfunction after sirolimus-eluting stent implantation: implication for late stent thrombosis.


Elevated concentration of Pentraxin 3 is associated with coronary plaque vulnerability.


Long-term local inflammatory response after coronary artery stenting with drug-eluting stent.


C-type natriuretic peptide ameliorates the progression of experimental autommune myocarditis.


Assessment of Left Atrial Ejection Force in Patients with Hypertensive Heart Disease.

Journal of the American Society of Echocardiography


Importance of Left Atrial Function in Cardiac Response to Increment of Preload in Patients with Old Myocardial Infarction: Assessment by Automated Left Atrial Volume Tracking Method.


Beat-To-Beat Variation of Mitral Annular Velocities in Atrial Fibrillation.


The Mitral L-Wave Predicts the Cardiac Response to Preload Increment in Atrial Fibrillation.


Usefulness of Tei Index in Atrial Fibrillation: Assessment by Dual Doppler Echocardiography.


Multicenter Trial for the Validation of Automated Function Imaging in Patients with Local Left Ventricular Asynergy (VANILLA Study).


Role of Left Atrial Function for Pseudonormalization of Transmitral Flow Velocity Pattern in Patients with Hypertrophic Cardiomyopathy.


Assessment of the cardiac response to increment of preload in patients with atrial fibrillation using dual pulsed Doppler echocardiography.


Measurement of left atrial volume curve by advanced 2D tissue tracking technique: validation by contrast multidetector computed tomography.


Relationship Between the Ratio of Peak Early Diastolic Transmitral Flow and Mitral Annular Velocities and the Plasma B-Type Natriuretic Peptide (BNP) Concentration in Patients with Atrial Fibrillation: Assessment by Simultaneous Recording of Transmitral Flow and Mitral Annular Velocity.

Journal of the American College of Cardiology


Right Ventricular Apical Pacing Impairs Left Ventricular Torsion as Well as Synchrony.


Effect of aging on left atrial myocardial strain evaluated by 2D tissue tracking during lower body positive pressure.


Differentiation of left atrial dysfunction by changes in transmitral flow velocities during lower body positive pressure.


Difference in the Left Atrial Function Between Patients With Hypertensive Hypertrophy and Hypertrophic Cardiomyopathy Evaluated by Tissue Strain Imaging.


Ghrelin Protects Myocardium Against Ischemia/Reperfusion Injury via Inhibiting Myocardial Apoptosis.


Incomplete Relaxation and Excess Left Ventricular End-Diastolic Pressure during Atrial Fibrillation.


Long-term left ventricular morphologic change in hypertrophic cardiomyopathy: a relationship with development of atrial fibrillation.

Journal of the American Society of Echocardiography


Pseudonormalization of the transmitral inflow Doppler velocities re-evaluated in relation to the left atrial function using tissue strain imaging.


Quantitative assessment of biphasic response to dobutamine by tissue strain echocardiography.


Quantitative and Direct Assessment of the Left Atrial Reservoir Function Using Tissue Strain Imaging.


Decreased Arrhythmia Vulnerability in a Novel Rabbit Model of Left Ventricular Aneurysm Repair.


Effect of Left Ventricular Geometry on Systolic Myocardial Velocity Gradient in Patients With Hypertension.


Left Ventricular Long Axis Function Shows an Atypical Allometric Scaling to Ventricular Size.


Endothelial AT1 Receptor Overexpression Produces Hypotension and Bradycardia in mMice: The Role of Nitric Oxide.


Effect of Alteration of Left Ventricular Activation Sequence on the Left Ventricular Torsional Deformation in Anesthetized Closed-chest Dogs.


Intracardiac Doppler echocardiographic assessment of left atrial function pre and post pulmonary vein isolation for prediction of short-term recurrence of atrial fibrillation.


Comparison of left and right atrial stunning after conversion of chronic atrial fibrillation to sinus rhythm.


Natale A Intracardiac Doppler assessment of left atrial function immediately Post-Pulmonary Vein Isolation maybe predictive of short-term recurrence of atrial fibrillation.


Coupled Pacing Improves Stroke Work Without Increasing Myocardial Oxygen Consumption During Acute Heart Failure and Atrial Fibrillation.


Frank Starling Mechanism Is an Independent Contributor to Ventricular Performance Variability in Atrial Fibrillation.

Journal of the American College of Cardiology


Assessment of Left Ventricular Torsional Deformation by Doppler Tissue Imaging: A Validation Study Using Tagged Magnetic Resonance Imaging.


Assessment of Ventricular Untwisting Recoil Velocity by Doppler Tissue Echocardiography: An Index of Relaxation Time Constant.


Rate Control by Coupled Pacing During Atrial Fibrillation Increases Myocardial Efficiency.


Clinical Features of Mixed Physiology of Constriction and Restriction.


Assessment of Longitudinal and Radial Mitral Annular Movement in Left Ventricular Dysfunction Using Automated Mitral Annular Tracking.


Effect of Ventricular Slowing During Atrial Fibrillation on Relationship Between Cycle Length Irregularity and Mitral Annular Velocity: A Chronic Conscious Canine Model.


Left Atrial Appendage Flow Velocity During Atrial Fibrillation Predicts the Degree of Stunning After Conversion to Sinus Rhythm: Assessment by Intracardiac Echocardiography in Patients Undergoing Pulmonary Vein Isolation Ablation.


Coupled Pacing: A Novel Method To Improve Left Ventricular Pump Function During Atrial Fibrillation with Heart Failure.


Ventricular Slowing by AV Nodal Vagal Stimulation Improves Left Ventricular Systolic Function During Atrial Fibrillation: A Chronic Study in Conscious Canines.


Better Choice of Color Tissue Doppler Imaging Couped with High Dose Dobutamine Stress Echocardiography for Detection Coronary Artery Stenoosis.

Journal of the American Society of Echocardiography


Assessment of the Left Ventricular Diastolic Function Independent of Cardiac Translation Using a Newly Developed Tissue Strain Imaging.


Impact of Angiotensin II receptor Antagonist on Left Ventricular Myocardial Function on Hypertensive Hypertrophy: Assessment of Myocardial Velocity Profile and Plasma Vasoactive Peptide.


Tssue Doppler, Displacement, and Strain Rate in Acute Myocardial Ischemia.


Assessment of Left Atrial Conduit Volume in Patients with Hypertrophic Cardiomyopathy Using Real-Time Three-Dimensional Echocardiography.


Tissue Doppler Echocardiography in Normal and myocardial Infarction Rats: Mitral Annular Velocity, Myocardial Strain and Strain Rate.


Temporal Relation Between Left Ventricular Torsional, Longitudinal and Radial Recoil in Early Diastole Assessed by Tissue Doppler Echocardiography.


Assessment of Left Ventricular Twisting During Exercise Using Tissue Doppler Echocardiography.


Assessment of Left Atrial Systolic Function During Isovolumetric Atrial Contraction: Interest of the Pulmonary Vein Flow A-Reversal Peak Velocity-About Eight Acute Normal Dogs Experiment.

Journal of the American College of Cardiology


Longitudinal Myocardial Displacement and Strain Rate in the Hypertrophied Heart Evaluated by Tissue Strain Imaging With Doppler Angle Correction and Tissue Tracking Technique.


Recovery of Left Atrial Function Following Pulmonary Vein Isolation Using Radiofrequency Ablation in Chronic Atrial Fibrillation: An Intracardiac Doppler Echocardiographic Study.


Wringing Motion of Normal Left Ventricle Quantified With Tissue Doppler Echocardiography.


Does Pericardiectomy Improve Outcome of Patients With Mixed Constriction and Restriction?


Ascorbic Acid Accelerates Left Atrial Mechanical Recovery Following a Brief Duration of Atrial Fibrillation.


Correlation of Left Atrial Mechanical and Electrical Remodeling Following Short Duration Atrial Fibrillation.


Left Atrial Reservoir and Active 'Pump' Function after Brief Duration of Atrial Fibrillation: An Acute Animal Study.


A new method for assessing left atrial systolic function during isovolumetric atrial contraction in the intact heart. An animal study.


Early Diastolic Mitral Annular Tissue Doppler Velocities Predicts the Degree of Left Atrial Appendage Stunning Following Conversion to Sinus Rhythm after Short Duration Atrial Fibrillation in a Canine Model.


Long-term vagally controlled ventricular rate in atrial fibrillation.


First successful demonstration of vagally controlled ventricular rate during AF in chronically instrumented dogs.


Bigeminal Pacing: A Novel Method to Improve Left Ventricular Pump Function during Atrial Tachycardia and Fibrillation.


Importance of Passive Relaxation of the Left Atrial Appendage in Recovery from Stunning after Conversion of Atrial Fibrillation to Sinus Rhythm.


The "Pseudo-Restrictive" Pattern of Transmitral Doppler Flow Following Conversion of Atrial Fibrillation to Sinus Rhythm: Is Atrial Or Ventricular Dysfunction to Blame?


Automated Tracking of Mitral Annular Motion Using Two-Dimensional Echocardiography for Evaluation of Left Ventricular Function: A Comparison With Real-Time Three-Dimensional.


Temporal change in the left ventricular transmyocardial systolic velocity profile evaluated by color tissue Doppler imaging.

Journal of the American Society of Echocardiography


Noninvasive assessment of myocardial ischemia and necrosis using a newly developed tissue Doppler myocardial velocity profile.


Effect of angiotensin II receptor antagonist on left ventricular myocardial relaxation abnormality in hypertensive patients: evaluation using a newly developed myocardial velocity profile.


Quantitative analysis of the left ventricular segmental contractility in the normal subjects using newly developed angle-corrected tissue strain imaging.


Novel index for evaluating wall motion abnormality using newly developed angle-corrected tissue strain imaging.


Determinants of the left ventricular myocar-dial contractility in patients with hypertension evaluated by echocardiography.


Impact of infarct size on the end-systolic pressure-area relation of remote non-infarcted myocardium in chronic myocardial infarction: an animal study.


Demonstration of vagally controlled ventricular rate potential interest during AF in chronically instrumented dogs. First experience.


Ventricular rate slowing improve left atrial appendage function in atrial fibrillation. Potential interest to vagal nerve stimulation to control atrio-ventricular conduction.


Assessment of the longitudinal (apex to base) myocardial velocity profile using tissue Doppler imaging in sheep with chronic myocardial in-farction.


Effect of an increase in afterload on tissue Doppler derived systolic myocardial velocity gradient.


"Stunning" after a brief duration of atrial fibrillation is greater in the left atrial appendage than left atrium.


Ascorbic acid accelerates left atrial functional recovery following a short duration of atrial fibrillation.


Pulmonary Venous Atrial Systolic Flow Reversal Velocity During Ventricular Systole Predicts Left Atrial Elastance: A New Method for Assessing Left Atrial Systolic Function in an Animal Model.

Journal of the American College of Cardiology


Myocardial Characterization of Cardiac Amyloidosis Using Myocardial Velocity Profile: Comparison With Hypertensive Heart Disease.


Novel Strategy for Detecting Myocardial Viability by Evaluating Improvement of Early Diastolic Left Ventricular Asynchrony Using Dobutamine Stress Pulsed Tissue Doppler Imaging.


Assessment of Nonuniformity of the Transmural Myocardial Velocity Profile by Angle Corrected Tissue Doppler Imaging: Characterization of Normal, Transmurally Infarcted and Nontrasmurally Infarcted Myocardium.


Rate Control During Atrial Fibrillation Improves Left Ventricular Relaxation Better Than Rhythm Regulation with Atrioventricular Node Ablation.


The Role of Short and Long Axes Function for Determining Late Diastolic Left Ventricular Filling in Patients with Hypertension.


Prognostic value of atrial systolic mitral annulus motion velocity in patients with dilated failing heart.

Journal of the American Society of Echocardiography


Early Diastolic Transmural Myocardial Velocity Profile Evaluated by Tissue Doppler Imaging in Normal Subjects and Patients With Left Ventricular Hypertrophy.


Accurate Measurement of Systolic Transmural Myocardial Velocity Profile Using Tissue Doppler Imaging in Normal Subjects And Patients with Hypertrophic Cardiomyopathy.


The Role of Short And Long Axes Function for Determining Late Diastolic Left Ventricular Filling in Patients with Hypertension: Assessment by Pulsed Tissue Doppler Imaging.


Potential Application of Tissue Doppler Imaging of the Left Ventricular Myocardium in Assessing Regional Diastolic Function in Patients with Hypertrophic cardiomyopathy: Comparison with 1231-b-Methy1 Iodopheny1 Pentadecanoic Acid Myocardial Scintigraphy.


Improvement in Left Ventricular Function during Atrial Fibrillation in Subjects with Myocardial Infarction Using Post-ganglionic Vagal Nerve Stimulation.


Accurate Measurement of Early Diastolic Transmural Myocardial Velocity Profile Using Tissue Doppler Imaging in Normal Subjects and Patients with Left Ventricular Hypertrophy.


Ultrasonic myocardial characterization of cardiac amyloidosis using tissue Doppler imaging.


Quantitative assessment of left ventricular myocardial viability using systolic mitral annular descent velocity: A study with dobutamine stress pulsed tissue Doppler imaging.


Myocardial gradient as an indicator of regional myocardial contraction after cardiac surgery: a study with tissue Doppler imaging.


Regional left ventricular myocardial function in hypertrophic cardiomyopathy: assessment by tissue Doppler imaging and 123 I-b-methyliodopheny1 pentadecanoic acid scintigraphy.


Assessment of left ventricular myocardial viability using mitral annular descent velocity: a study with dobutamine stress pulsed tissue Doppler imaging.


Assessment of diastolic left ventricular myopcardial velocity gradient in hypertrophic cardiomyopathy using tissue Doppler imaging: Comparison with 123I-BMIPP myocardial washout ratio.


Evaluation of left ventricular myocardial viability using mitral annular descent velocity: A study with dobutamine stress pulsed tissue Doppler imaging.


Mechanism of systolic left ventricular asynchrony in normal heart: A study with Angiotensin II stress pulsed tissue Doppler imaging.


Left ventricular subendocardial systolic velocity in dilated and hypertrophic cardiomyopathy: Pulsed tissue Doppler imaging of short and long axis motion.


Response of left ventricular systolic wall motion velocity during low-dose Angiotensin II stress tissue Doppler imaging in patients with hypertrophic cardiomyopathy.

Journal of the American College of Cardiology


Assessment of early diastolic left ventricular regional myocardial function in patients with hypertrophic cardiomyopathy using tissue Doppler imaging and magnetic resonance myocardial tagging.


Relationship between left atrial appendage function and plasma concentration of atrial natriuretic peptide.


Evaluation of left atrial relaxation abnormality using pulmonary venous flow velocity and interatrial septal motion.


Differentiation of left ventricular diastolic wall motion velocities between aortic and mitral regurgitation using tissue Doppler imaging.


Relationship between left ventricular regional wall motion abnormalities and mitral annular descent velocities in patients with myocardial infarction and dilated cardiomyopathy: a study with tissue Doppler imaging.


Influence of aging on early diastolic and atrial systolic motion dynamics of the left ventricular wall in normal subjects: Vector analysis of the wall motion velocities using pulsed tissue Doppler imaging.

Journal of the American Society of Echocardiography


Evaluation of left ventricular regional systolic wall motion velocity in hypertrophied hearts using pulsed tissue Doppler imaging.


Evaluation of electrical and mechanical discordance during atrial systole using pulsed tissue Doppler imaging.


Clinical application of pulsed Doppler tissue imaging for assessing abnormal relaxation of the left ventricle.


Roles of left atrial appendage for left atrial hemodynamics by left atrial appendage clamping during cardiac surgery.


Assessment of myocardial circumferential shortening of the left ventricular wall using pulsed Doppler tissue imaging.


Non-invasive assessment of left ventricular relaxation by pulsed Doppler tissue imaging: comparison with cardiac catheterization.


Evaluation of left ventricular diastolic function in hypertrophied hearts using Doppler tissue imaging.


Evalution of left ventricular diastolic function in hypertrophied hearts using Doppler tissue imaging.


Coronary flow velocity immediately after reperfusion reflects myocardial microcirculation in canine acute myocardial infarction models.

Journal of the American College of Cardiology


Influence of left atrial pressure on the left atrial appendage flow velocity pattern.


Effect of left atrial pressure on the rate of left ventricular relaxation estimated by mitral regurgitant flow velocity using continuous wave Doppler echocardiography in dilated heart.


Transesophageal pulsed Doppler echocardiographic evaluation of left atrial systolic performance in hypertrophic cardiomyopathy.


Influence of ageing on left atrial appendage flow velocity pattern in healthy subjects with sinus rhythm: a study with transesophageal pulsed Doppler echocardiography.


Influence of left atrial pressure on the left atrial appendage flow velocity pattern in myocardial diseases with sinus rhythm.


Preload Stress Echocardiography for the Assessment of Heart Failure With Preserved Ejection Fraction


Identifying the extent of oral fluid droplets on echocardiographic machine consoles in COVID-19 era


亀田徹氏らによる「Bラインを用いたpoint-of-care超音波による心原性肺水腫の評価」 (超音波医学 2018 ; 45 : 1252-135)を拝読して / 水関清氏の論評に対する回答


Effects of Transthoracic Echocardiographic Simulator Training on Performance and Satisfaction in Medical Students.

Journal of the American Society of Echocardiography