SummaryWhen ingested at doses exceeding 1 g, tricyclic antidepressant drugs may cause serious cardiovascular disturbances. These are caracterized by a decrease in cardiac output with arterial hypotension, arrhythmias of supraventricular and ventricular origin and disturbed conduction at all stages. These phenomena are due the direct cardiotoxic and the anticholinergic effects of these drugs. With appropriate treatment they are mostly reversible.