title: Tricyclic antidepressants and cardiac conduction: changes in ventricular automaticity.
abstract: Ventricular dysrhythmias result from changes in the automaticity or the conduction properties of the specialized conduction system. Tricyclic antidepressants have been reported to cause ventricular dysrhythmias in humans and experimental animals. Consequently, it seemed to interest to determine whether these substances influence ventricular automaticity. Ventricular rhythm was produced in anesthetized dogs by blocking atrioventricular conduction. Low doses of imipramine, amitriptyline and nortriptyline resulted in small but significant increases in automaticity. Relatively high doses of these agents suppressed automaticity markedly. These changes could play a role in the development of dysrhythmias.
mesh_terms: D000639:Amitriptyline / Q000494:pharmacology; D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D005260:Female; D006325:Heart Atria / Q000187:drug effects; D006329:Heart Conduction System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006352:Heart Ventricles / Q000187:drug effects; D007099:Imipramine / Q000494:pharmacology; D008297:Male; D005996:Nitroglycerin / Q000494:pharmacology; D009661:Nortriptyline / Q000494:pharmacology
chemical_list: D000929:Antidepressive Agents, Tricyclic; D000639:Amitriptyline; D009661:Nortriptyline; D005996:Nitroglycerin; D007099:Imipramine