Continuous-wave Doppler echocardiography for evaluating left ventricular performance. Clinical significance of a new systolic time interval.

Left ventricular performance was evaluated in 51 patients with acute myocardial infarction and angina pectoris using parameters derived from the flow velocity waveform at the ascending aorta. Flow velocity waveforms were obtained from the suprasternal notch by continuous-wave Doppler echocardiography and were recorded on a line-scan recorder at a paper speed of 100 mm/sec with lead II ECG. The peak flow velocity and the systolic time interval from the beginning of ECG Q wave to the peak flow velocity (Q-V peak interval) were measured. Relationships were investigated between these parameters and the left ventricular ejection fraction (LVEF) obtained from multigated equilibrium blood pool imaging with 99mTc-pertechnetate. The peak flow velocity did not correlate with LVEF (r = 0.27). However, a highly significant negative correlation was observed between the systolic time interval Q-V peak and LVEF (r = -0.84, p less than 0.001). The regression equation was LVEF = -0.46 X (Q-V peak) + 142. We conclude that left ventricular performance can be evaluated in patients with coronary artery disease at the bedside using the Q-V peak interval measured from simultaneous recording of the velocity waveform at the ascending aorta and the ECG.