The use of the first derivative of apex cardiogram and echocardiographic dimensions for assessing left ventricular relaxation and mean velocity of circumferential fibre lengthening in cardiomyopathy.

Abstract

Eleven patients with hypertrophic obstructive cardiomyopathy (HOCM) and nine patients with congestive cardiomyopathy (COCM) were studied to determine the usefulness of relaxation time and mean velocity of circumferential fibre lengthening (VCFJ obtained from the first derivative of apex cardiogram and echocardiographic left ventricular dimensions. Twenty-two normal patients were ± investigated by echo and apex cardiography and served as controls. In HOCM both early apex cardiographic relaxation time interval (ERT) and total apex cardiographic relaxation time interval (TRT) were increased (ERT: 16 ±9 ms v. 5 ± 4 ms in controls, P<O.001; TRT: 127 ± 22 ms v. 94 ± 21 ms in controls, P<O.01) and VCFL was decreased (0.87 ± O.08 circs v. 1.21± O.09 circ/s for controls, P<0.02). In COCM both ERT and TRT were diminished (ERT: 1 ± 3.5 ms v.7±4 ms in controls, P<O001; TRT: 53 ± 14 ms v. 94 ± 21 ms for controls, P<O.01) and VCFL was decreased (0.69 ± 0.08 circ/s v. 1.21 ±0.09 circ/s in controls, P<O.01). There was a significant correlation between min dp/dt determined at catheterization and both ERT (r = O.86) and TRT (r=O.81). These findings indicate that alterations in relaxation and mean velocity of circumferential fibre a lengthening take place in cardiomyopathy and they may be detected non-invasively by the first derivative of the apex cardiogram and the left ventricular echocardiogram.