Doppler measurement of left ventricular isovolumic intervals: a study of feasibility and correlation with conventional techniques.

Pulsed Doppler echocardiography allows simultaneous recording of left ventricular inflow and outflow blood velocities obtained from the apical 5-chamber view. In this study the feasibility and accuracy of pulsed Doppler measurements of left ventricular isovolumic relaxation and contraction times were compared with those derived from two conventional techniques that combined phonocardiograms and M-mode echograms (phono-echo) and M-mode echograms and electrocardiograms (ECG-echo). Thirty-seven subjects--24 healthy volunteers and 13 cardiac patients--were examined. Isovolumic relaxation was consistently longer than isovolumic contraction time. Younger age was associated with shorter isovolumic intervals, while heart rate had a negative correlation with these parameters (r = -0.5). Pulsed Doppler measurements of isovolumic relaxation correlated well with phono-echo, r = 0.89, and ECG-echo, r = 0.75. Isovolumic contraction times measured by Doppler correlated better with those derived by phono-echo, r = 0.75, than those by ECG-echo, r = 0.4. Better correlations were found for both measurements in the normal subgroup than in the whole group. Difficulty was encountered in measuring isovolumic contraction time by Doppler and ECG-echo in the absence of presystolic A-wave, and in subjects with varying cardiac cycle lengths. Thus, pulsed Doppler measurements of left ventricular isovolumic relaxation times were feasible and consistent with the other methods, while isovolumic contraction intervals by Doppler were not.