[Paradoxical left ventricular blood flow during the isovolumic relaxation period in non-obstructive hypertrophic cardiomyopathy: Doppler and M-mode echocardiographic study].

The left ventricular blood flow pattern during the isovolumic relaxation period was investigated in 17 patients with apical hypertrophy (mean 54 +/- 8 years) and 30 with asymmetric septal hypertrophy without left ventricular outflow obstruction (mean 54 +/- 14 years). Thirty-five age-matched normal subjects served as controls (mean 51 +/- 10 years). All cases were examined by pulsed Doppler echocardiography simultaneously with phonocardiography. In all the control subjects, an apically-directed flow was observed, which occurred simultaneously with the onset of the second heart sound. In contrast, a basally-directed flow was detected during the isovolumic relaxation period in 13 patients (76%) with apical hypertrophy and in 28 (93%) with asymmetric septal hypertrophy. In these cases, an apically-directed flow was often observed before the second heart sound. Standard M-mode echocardiography revealed a significant increase in the left ventricular short-axis dimension at the base during the isovolumic period in patients with hypertrophic cardiomyopathy, while the normal controls showed no significant change. Moreover, peak velocity of the basally-directed flow correlated significantly with the rapidity of dilatation of the basal dimension (r = 0.61, p less than 0.01). Thus, this basally-directed blood flow in the left ventricle during the isovolumic relaxation period may be caused by the asynchronous left ventricular dilatation during the isovolumic period.