Time variation of mitral regurgitant flow in patients with dilated cardiomyopathy.

Abstract

Angiographic results in patients with mitral regurgitation suggest that up to 50% of the regurgitant volume occurs during the preejection period. This contrasts markedly with the electromagnetic measurements of mitral regurgitant flow in anesthetized dogs, which suggest that only 5% of mitral regurgitant flow occurs during the preejection period. Therefore, we used two-dimensional and Doppler echocardiography to quantify mitral regurgitation during aortic ejection and in the preejection and postejection periods in eight patients with severe heart failure. Mitral regurgitant volume (RV) was calculated as the difference between total stroke volume (by two-dimensional echocardiography) and forward aortic flow (by pulsed Doppler). Regurgitant velocity (V) and time (RT) were measured by continuous-wave Doppler, and the mean regurgitant area (RAm) was calculated from the RT and mean regurgitant velocity (Vm): RAm -(RV/RT)/Vm. As a first approximation, the RA was assumed to be constant during systole, and the regurgitant volume during aortic ejection and during the preejection and postejection periods was calculated from: RVi = (Vmi) (RTi) (TAm), where Ti represents the duration of the appropriate period. Percentages of total regurgitant volume occurring during the preejection, ejection, and postejection periods were 13 + 4%, 79 + 5%, and 8 + 5%. respectively. Thus, in contrast to previously reported angiographic studies, mitral regurgitation occurs predominantly during the aortic ejection period. These results were not substantially changed by assuming a 20% reduction in effective regurgitant orifice area between the preejection and ejection periods and are consistent with data from chronically instrumented dogs with mitral regurgitation. Furthermore, our findings are supported by a computer model of the central circulation that was modified to include an incompetent mitral valve. The model offers significant insight into the physiologic mechanisms governing phasic changes in mitral regurgitant volume. Circulation 74, No. 4, 684-692, 1986. CLINICAL STUDIES of angiographically measured mitral regurgitant volume have concluded that 25% to 46% of the total volume is regurgitated during the preejection period. '

Echocardiographic Assessment of the Interventricular Delay of Activation and Correlation to the QRS Width in Dilated Cardiomyopathy

“…Xiao et al 15 reported electromechanical delay to activate the LV in DCM patients with a wide QRS that was evaluated from the onset of the QRS to the onset of MR, negatively correlated to the PR duration and reduced when compared to controls with narrow QRS duration. Preload and afterload conditions, duration of LV filling, and the PR interval interfered with the time course of the MR, 16 and this electromechanical delay may not be comparable with the time for LV activation measured in the present study.…”

Three-dimensional echocardiographic assessments of exercise-induced changes in left ventricular shape and dyssynchrony in patients with dynamic functional mitral regurgitation

“…1 In normal condition, the stroke volume gradually increases during exercise, 2,3 whereas in HF patients, exercise-induced changes in forward stroke volume have been shown to be inversely related to the extent of dynamic mitral regurgitation (MR). [4][5][6] Functional MR, a frequent condition in HF, is characteristically dynamic with intermittent changes in regurgitant volume in relation with loading conditions, [5][6][7][8][9] changes in LV shape, and dynamic LV dyssynchrony. 9,10 An exercise increase by !13 mm 2 in mitral effective regurgitant orifice is associated with a three-fold greater risk of cardiac-related death.…”

Echocardiographie Findings in Patients with Regurgitation of All Cardiac Valves

“…Regurgitation of left-sided cardiac valves is more commonly associated with structural abnormalities of either the valves or the supporting structures [1][2][3][4][5]. The development of regurgitation of all 4 cardiac valves, then, would appear to require abnormalities of the left sided cardiac valves and pulmonary hypertension.…”

“…Seven patients had severely dilated left ventricles with a mean left ventricular end-diastolic dimension of 7.4 ± 0.8 cm (p < 0.01), without evidence of calcification of mitral or aortic valves. The third group consisted of 2 young patients with rheumatic heart disease, 1 with severe mitral stenosis, and the other with rheumatic aortic and mitral insufficiency.The detection of valvular regurgitation has become one of the major clinical applications of Doppler echo cardiography [1][2][3][4][5][6][7][8][9][10][11]. In recent years, it has become obvious that some of the regurgitation that is detected is of academic interest only, with little clinical significance [12][13][14], Regurgitation in the absence of cardiac pathol ogy is most commonly seen in the tricuspid and pul monic valves [7][8][9][10][11], We undertook this study to exam ine the frequency of Doppler-detected regurgitation of all 4 cardiac valves in a hospital-based echocardiography laboratory, and to determine what underlying échocar diographie features are seen with regurgitation of all 4 cardiac valves.…”