Usefulness of early diastolic flow propagation velocity measured by color M-mode Doppler technique for the assessment of left ventricular diastolic function in patients with hypertrophic cardiomyopathy

Flow propagation velocity (FPV) of left ventricular (LV) filling flow has b een shown to be a useful index for the evaluation of LV diastolic function, which is relatively independent of preload in myocardial infarction and di lated cardiomyopathy, but the usefulness of FPV for hypertrophic cardiomyop athy (HCM) has not yet been determined. In 23 HCM patients and 26 control s ubjects, peak transmitral flow velocities in early diastole (E) and during atrial contraction (A), E/A ratio, deceleration time of E velocity, and iso volumic relaxation time were measured with the conventional Doppler techniq ue, and FPV was measured from color M-mode Doppler images of LV filling flo w. The time constant of LV isovolumic pressure decay (tau) was measured by a micro-manometer-tipped catheter in all HCM patients and 13 control subjec ts. Flow propagation velocity was significantly lower and deceleration time was significantly greater in HCM patients than in the control subjects, th ough no significant differences were observed in the other noninvasive inde xes. Tau was significantly prolonged in HCM patients compared with that of control subjects (54 +/- 12 cm/s and 32 +/- 7 cm/s, respectively; P < .0001 ). while the conventional indexes did not correlate with tau among the 36 p atients in whom invasive studies were performed, FPV correlated well with t au (r = -0.76, P < .0001). Flow propagation velocity is a useful noninvasiv e index for the assessment of LV diastolic function in patients with HCM.