Left ventricular diastolic function in congenital myotonic dystrophy

Abstract

Objective - Examination of left ventricular function and conduction abnormalities in myotonic dystrophy. Design - Twelve patients (median age, 13.7 years) with myotonic dystrophy had detailed electrocardiography and echocardiography performed. Echocardiographic parameters were compared with body surface area (BSA) matched median normal values. Results - Fractional shortening was slightly reduced (by 28-29%) in three patients and three patients had mild mitral valve prolapse. Diastolic function was abnormal; isovolumic relaxation time (IVRT) and duration of early filling were prolonged compared with control values (median IVRT, 74 v 61 ms). Peak E velocity was increased (median, 0.82 v 0.78 m/s) but atrial phase filling was normal. Heart rate was reduced (median, 68 v 81 beats/min). Conduction abnormalities were common but showed no clear relations with diastolic abnormalities. Conclusions - Young patients with myotonic dystrophy have myocardial diastolic dysfunction as well as abnormal electrophysiology. The prognostic implications of such abnormalities require further study.