Effects of imipramine and amitriptyline on intraventricular conduction, effective refractory period, incidence of ventricular arrhythmias induced by programmed stimulation, and on electrocardiogram after myocardial infarction in dog.
The effects of imipramine and amitriptyline on intraventricular conduction, effective refractory period, incidence of ventricular arrhythmias induced by programmed stimulation and on electrocardiogram changes were studied after myocardial infarction in the dog. Amitriptyline, at doses of 1-3 mg/kg, significantly slowed the ventricular conduction of the infarcted zones in a dose- and frequency-dependent manner. Amitriptyline, at doses of 2 and 3 mg/kg, slowed the ventricular conduction slightly in the normal zone. The effective refractory period was prolonged by amitriptyline at a dose of 1 mg/kg. Amitriptyline increased the incidence of ventricular arrhythmias induced by programmed stimulation. Amitriptyline, at doses of 1-3 mg/kg, increased heart rate and prolonged the PQ, QRS and QT interval. Imipramine, at a dose of 3 mg/kg, slowed the conduction in infarcted zones to a lesser extent than amitriptyline. Imipramine, at doses of 1 and 2 mg/kg, did not significantly increase the incidence of ventricular arrhythmias. Imipramine, at a dose of 3 mg/kg, prolonged the QRS interval. From the present results it appears that imipramine has a lower cardiac toxicity than amitriptyline.
Nishimoto
M
M
Department of Pharmacology, Hamamatsu University School of Medicine, Japan.
Hashimoto
H
H
Ozaki
T
T
Taguchi
T
T
Ohara
K
K
Nakashima
M
M
D000639:Amitriptyline / Q000494:pharmacology / Q000627:therapeutic use / Q000633:toxicity*; D000704:Analysis of Variance; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial; D004195:Disease Models, Animal; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D004562:Electrocardiography / Q000187:drug effects; D004594:Electrophysiology; D006329:Heart Conduction System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006352:Heart Ventricles / Q000187:drug effects / Q000503:physiopathology; D007099:Imipramine / Q000494:pharmacology / Q000627:therapeutic use / Q000633:toxicity*; D009203:Myocardial Infarction / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D012032:Refractory Period, Electrophysiological / Q000187:drug effects
D000639:Amitriptyline; D007099:Imipramine