Effects of left ventricular dysfunction on left atrial performance in previous myocardial infarction and during pacing-induced myocardial ischemia in angina pectoris

Impact of left ventricular function on the pulmonary vein Doppler spectrum: nonsimultaneous assessment with load-insensitive indices

Pulmonary vein Doppler spectrum is highly load-dependent and thus has been used to estimate left ventricular (LV) filling pressure. However, the impact of LV function on pulmonary vein Doppler spectrum remains obscure because only load-sensitive indices were studied previously. In the present study, measurements of the pulmonary vein Doppler spectrum were correlated with load-insensitive LV systolic (end-systolic elastance [Ees]) and diastolic (relaxation time constant [tau] and beta coefficient of the end-diastolic pressure volume relationship) function indices obtained from an invasive catheterization study nonsimultaneously. The peak velocity, velocity time integral, and duration of systolic forward spectrum were significantly correlated with Ees (r = 0.35, r = 0.36, and r = 0.41, respectively;P < 0.05). The pulmonary vein diastolic velocity time integral (PVDVTI) and duration of the diastolic forward spectrum were significantly correlated with Ees (r = 0.51 and r = 0.57, respectively;P < 0.01). PVDVTI was correlated with tau and the end-diastolic pressure-volume relationship (EDPVR) (r = 0.42 and r = 0.40 respectively,P < 0.05). On the other hand, the systolic fraction of the forward spectrum was significantly correlated with ejection fraction (for peak velocity,r = 0.63, P < 0.01; for velocity time integral,r = 0.37, P < 0.05) but not with Ees, and the diastolic fraction of the forward spectrum was significantly correlated with minimum pressure derivative over time (for peak velocity,r = 0.48, P < 0.05; for velocity time integral,r = 0.44, P < 0.05, respectively) but not with tau or EDPVR. In summary, the systolic and diastolic components of the pulmonary vein Doppler spectrum are affected variably by LV systolic and diastolic function, independent of the loading condition. The systolic and diastolic fraction of pulmonary vein Doppler spectrum appears to depend more on the loading condition than the LV systolic or diastolic function.

Echocardiographic determination of left atrial function and its application for assessment of mitral flow velocity pattern

We determined left atrial (LA) volume changes to evaluate LA function, and to correlate the Doppler-determined mitral flow velocity (MFV) pattern. Twenty-four patients with ischemic heart disease who showed 'normal' MFV pattern by pulsed Doppler echocardiography were studied. The patients were divided into 14 patients with left ventricular end diastolic pressure < 18 mmHg (true normals) and 10 patients with > or = 18 mmHg (pseudo normals). The changes in LA volume were determined by echocardiography from apical two- and four-chamber views with modified Simpson's method. The volume measurements were done at the time of mitral valve opening (Vmax), at onset of atrial systole (Va) and at mitral valve closure (Vmin). Then the passive LA emptying volume was calculated by subtracting Va from Vmax, and the active LA emptying volume by subtracting Vmin from Va. The LA ejection fraction was calculated by the formula: [(Va-Vmin)Va] x 100. There was no significant difference in LA ejection fraction in pseudo normal (39+/-6%) and in true normal (41+/-13%) patients. Although the passive LA emptying volume was 16+/-4 ml/beat in true normal and was 11+/-3 ml/beat in pseudo normal (NS), the active LA emptying volume was significantly greater in pseudo normals (22+/-4 m/beat) than in true normals (12+/-2 ml/beat, P<0.001). Thus, the ratio of passive and active LA emptying volume was markedly greater in true normals (1.28+/-0.35) than in pseudo normals (0.52+/-0.19, P<0.001), facilitating the differentiation of these two groups. These results indicate that two-dimensional echocardiographic measurement of LA volume can be valuable in assessing the LA function, providing an alternative method for differentiating pseudo normal from true normal MFV pattern in clinical settings, although several technological shortcomings should be resolved.

What is the most appropriate variable for estimation of mean pulmonary capillary wedge pressure by transesophageal pulsed Doppler echocardiography?

Although left ventricular (LV) inflow and pulmonary venous (PV) flow variables estimated by transesophageal Doppler echocardiography (TEE) reflect pulmonary capillary wedge pressure (PCWP), they are also affected by changes in cardiac function. The purpose of the present study was to detect the most appropriate variable for the estimation of PCWP by TEE in patients (pts) with ischemic heart disease. Several variables of LV inflow and left upper PV flow were compared with PCWP in 36 pts (six with angina pectoris and 30 with old myocardial infarction). Early diastolic flow (E) and atrial contraction flow (A) were used as LV inflow, while systolic forward flow (X), diastolic forward flow (Y) and atrial contractile reversal flow (z) were used as PV flow. The peak velocity of each flow wave (Ep, Ap, Xp, Yp, and Zp) and the time-velocity integral (Ei, Ai, Xi, Yi, and Zi) were measured. The ratio of Ep to Ap (Ep/Ap), Ei to Ai (Ei/Ai), Xp to Yp (Xp/Yp), Xi to Yi (Xi/Yi), Zp to Ap (Zp/Ap), Zi to Ai (Zi/Ai) and the systolic fraction of PV forward flow were calculated. Among these variables, the Zi/Ai ratio was most strongly correlated with PCWP (R = 0.80). The Zi/Ai ratio may not be influenced by atrial function because the augmentation of atrial pump function increases Zi as well as Ai, and this may be one reason why the ratio correlated well with PCWP.

CONCLUSION

The Zi/Ai ratio is a new useful variable for estimating PCWP by TEE.

Left atrial myopathy in idiopathic dilated cardiomyopathy

To investigate whether left atrial systolic dysfunction in dilated cardiomyopathy is the result of left atrial dilatation, atrial involvement in the myopathic process, or both, 20 patients with aortic stenosis, 14 patients with idiopathic dilated cardiomyopathy, and 10 normal control subjects were studied. Left atrial volumes (cubic centimeters) were echocardiographically measured at mitral valve opening (maximal), mitral valve closure (minimal), and onset of atrial systole (P wave of the electrocardiogram) with the biplane area-length method. Atrial systolic function was assessed by calculating the active emptying fraction, equal to (volume at onset of atrial systole minus minimal volume)/volume at onset of atrial systole. Heart rate was similar in patients with aortic stenosis and dilated cardiomyopathy (83 +/- 11 vs 86 +/- 15 beats/min, respectively). Maximal volume was similar in patients with aortic stenosis (74.8 +/- 26.4 cm3) and dilated cardiomyopathy (79.7 +/- 25.3 cm3) but greater (p < 0.0001) than in control subjects (46.4 +/- 11.9 cm3). Active emptying fraction was inversely related to volume at onset of atrial systole and to tension at end of atrial systole (aortic stenosis r = -0.61 and r = -0.81, respectively; dilated cardiomyopathy r = -0.79 and r = -0.66, respectively). At any given level of volume at onset of atrial systole and tension at end of atrial systole, however, active emptying fraction was lower in patients with dilated cardiomyopathy compared with those with aortic stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Estimation of mean left atrial pressure from transesophageal pulsed Doppler echocardiography of pulmonary venous flow

To determine whether pulmonary venous flow and mitral inflow measured by transesophageal pulsed Doppler echocardiography can be used to estimate mean left atrial pressure (LAP), we prospectively studied 47 consecutive patients undergoing cardiovascular surgery. We correlated Doppler variables of pulmonary venous flow and mitral inflow with simultaneously obtained mean LAP and changes in pressure measured by left atrial or pulmonary artery catheters. Among the pulmonary venous flow variables, the systolic fraction (i.e., the systolic velocity-time integral expressed as a fraction of the sum of systolic and early diastolic velocity-time integrals) correlated most strongly with mean LAP (r = -0.88). Of the mitral inflow variables, the ratio of peak early diastolic to peak late diastolic mitral flow velocity correlated most strongly with mean LAP (r = 0.43), but this correlation was not as strong as that with the systolic fraction of pulmonary venous flow. Similarly, changes in the systolic fraction correlated more strongly with changes in mean LAP (r = -0.78) than did changes in the ratio of peak early diastolic to peak late diastolic mitral inflow velocity (r = 0.68). We conclude that in the surgical setting observed, pulmonary venous flow from transesophageal pulsed Doppler echocardiography can be used to estimate mean LAP. This technique may provide a rapid, simple, and relatively noninvasive means of gauging this variable in patients undergoing intraoperative transesophageal echocardiography.