Left ventricular diastolic function in congenital myotonic dystrophy

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