Relation between electrocardiographic repolarisation changes and mechanical events in left ventricular hypertrophy.

The relation between ventricular function and the presence of electrocardiographic "strain" in patients with left ventricular hypertrophy was examined using digitised M mode echocardiography and 12 lead electrocardiograms in 64 patients with pressure overload, 21 with hypertrophic cardiomyopathy, and 14 athletes. Although all had increased left ventricular mass, those with strain had a prolonged interval from minimum cavity dimension to mitral valve opening and a reduced rate of early diastolic posterior wall thinning and dimension increase compared with those with normal ST segments and T waves. Both groups had normal systolic function (fractional shortening and peak velocity of circumferential fibre shortening), and the time between the termination of the T wave and minimum dimension was similar. In athletes, however, electromechanical systole was shorter than normal, and the end of the T wave and minimum cavity dimension were synchronous. It is concluded that abnormal electrical recovery in left ventricular hypertrophy is closely related to impaired early relaxation and may be dissociated from impaired systolic function, cavity dimension, interventricular conduction delay, and the presence of increased mass alone. The normal relation between electrical and mechanical systole is preserved even when the polarity of repolarisation is reversed.