Doppler echocardiographic assessment of left ventricular isovolemic relaxation flow

It is not infrequent to observe a peculiar intraventricular relaxation flow (IRF) pattern during the isovolumic relaxation time (IRT), especially in patients (pts) with left ventricular hypertrophy (LVH). This is even more likely in pts with hypertrophic obstructive cardiomyopathy and in VVI-paced pts. Despite these observations, the prevalence and clinical relevance of this finding have not been evaluated thoroughly and systematically in a consecutive series of patients.

Ninety-two consecutive pts underwent a conventional Doppler echo study for the evaluation of systolic and diastolic function (fractional shortening, EF, E and A wave velocity, duration and ratio, and IRT). of these, 42 pts had LVH, 14 had mitral regurgitation (MR) with depressed EF, 8 had CAD with depressed EF and 28 were normal subjects. IF was searched for during the evaluation of IRT and its duration, velocity and integral were measured when noted.

Fifty-six patients (61%) showed an IRF at Doppler examination. Of these, fifteen were normal subjects (53%) and 34 (81%, p = 0.03 vs normal) were hypertensive pts. Among pts with depressed EF, only two of 14 with MR and 5 of 8 with no MR showed an IRF (14 vs 62%; p = 0.032). When evaluating LV function, we observed that pts with an IRF had a larger atrial filling fraction, a longer isovolumic relaxation time and a higher ejection fraction with respect to pts with no IRF (respectively, 40 +/- 13% vs 30 +/- 13%, p = 0.005; 108 +/- 23 ms vs 77 +/- 22 ms, p = 0.0001; 70 +/- 14% vs 61 +/- 16%, p = 0.01).

Our data confirm that IRF may be observed in healthy subjects and may be due to an asynchronous relaxation of the LV during IRT, in consideration of a higher prevalence of a greater atrial filling fraction in pts with IF as compared to those in whom this Doppler signal is absent. Moreover, IRF is more frequent in pts with LVH and is rare in pts with MR (predominantly due to a very short isovolumic relaxation time).