[Cardiac rhythm and conduction disorders in polymyositis and dermatomyositis].

To assess condition of the heart in polymyositis (PM) and dermatomyositis (DM) in terms of defects in the rhythm and conductivity, we carried out ECG, 24-hour ECG monitoring, EIA measurements of KPK MB-fraction and myoglobin, echocardiography and Doppler echocardiography. Maximal frequency of arrhythmia presenting as supraventricular and ventricular extrasystole occurred in patients with acute PM/DM. Blockade of the bundle of His left anterior branch was detected most frequently in patients with acute and subacute PM-DM and in those with high serum levels of KPK MB-faction and myoglobin. Frequency of rhythmic and conductivity disorders seems unrelated to the disease duration. We registered no alterations at rest either in intracardiac hemodynamics or myocardial contractility. The study of these parameters under exercise test may provide objective information on early defects in myocardial contractility.