Electrocardiographic evaluation of dogs experimentally infected with Trypanosoma cruzi during the acute and indeterminate chronic phases of infection

Abstract

Groups of dogs experimentally infected with Trypanosoma cruzi (1,000 trypomastigotes/kg body weight, Colombian strain) and infected and treated with a beta blocker (metoprolol) were submitted to electrocardiographic evaluation during the acute phase (weekly for 5 weeks) and during the chronic indeterminate phase (monthly for 6 months) with the objective of studying the degree of cardiac lesion. The alterations observed in the acute phase were more frequent in the infected group, with increased heart rate, mv suppression and increased PR interval, and increased heart rate persisted during the chronic
indeterminate phase. In the infected group treated with metoprolol there was mv suppression in the acute phase and maintenance of heart rate within normal limits in the chronic indeterminate phase. Other alterations such as increased Q wave, 1st and 2nd degree atrioventricular block, disorders of ventricular conduction, ventricular tachycardia, ventricular
extrasystole, asystole, and T wave suppression or increase, mainly occurred in the infected group during the acute phase.