Abstract
The cardiac effects of amitriptyline, mianserin, zimelidine and nomifensine on the systolic time intervals (STI) and on the high speed surface ECG have been studied in depressed patients. Amitriptyline increased pre-ejection period (PEP) index and the PEP/left ventricular ejection time (LVET) ratio of the STI (P less than 0.05 and P less than 0.02). It also increased heart rate significantly (less than 0.02) and tended to prolong Q-T interval. Mianserin shortened QS2I (P less than 0.05) and LVET (P less than 0.01) and prolonged PEP/LVET ratio (P less than 0.01). Zimelidine did not affect the STI but tended to decrease heart rate and prolong the Q-T interval. Nomifensine decreased T wave height. These findings indicate that amitriptyline decreases cardiac contractility and confirm the quinidine-like action of the tricyclic antidepressants. The changes brought about by mianserin are probably due to effects on the peripheral circulation rather than a direct action on the heart.