Etiology of cardiac arrhythmias

MI- commonest cause
Cardiomyopathy
Congenital e.g. congenital long QT syndrome d/t mutation in the gene encoding K channels
Myocarditis
Cardiac dilatation
Thyroid disorders
Electrolyte imbalance e.g. hypo or hyperkalemia
Drug induced e.g. cisapride, terfenadine etc