Pharmacological therapy of arrhythmias complicating dilated cardiomyopathy--implications of the arrhythmogenic substrate.

Dilated cardiomyopathy is a global myocardial abnormality in which it is likely that there are relatively homogeneous electrical conditions. The pattern of arrhythmic complications, especially atrial ectopic beats, ventricular ectopic beats and the brief salvoes of polymorphic ventricular tachycardia which are characteristic of the condition, suggest that triggered automaticity is a more likely arrhythmia mechanism than reentry. Although treatment with 'conventional' antiarrhythmic agents has an important place, drugs which alter myocardial loading conditions (and thus, thereby, a possible mechanism of triggered automaticity) may be effective. Therapeutic strategies directed against the basic disease processes are in an early stage of clinical development but they hold great promise for the future.