Electrocardiographic findings in naturally acquired chagasic heart disease in nonhuman primates

Abstract The significance of electrocardiographic (ECG) changes described in animals with Chagas' disease is questionable in view that other non-invasive comparisons have been lacking. 12-lead ECG and two-dimensional echocardiography (echo) was performed in 17 seropositive and 13 seronegative baboons. Similar to humans, a wide variety of ECG outcomes were observed in the infected animals. Standard ECG measurements were not different between groups. Five seropositive (29%) and 3 seronegative (23%) animals had low voltage; 4 seropositives (24%) and 2 (15%) seronegatives had tall P-waves. Precordial Q waves were seen in 10 seropositives (59%) and in 7 (54%) seronegatives without septal abnormalities on two-dimensional echo. One seropositive animal had a 2 nd degree (Wenckebach) AV block and left anterior fascicular block. Most animals in both groups had diffuse T-wave abnormalities. Echo evidence of systolic dysfunction was found in 4 seropositives and in none of the controls; thus, chagasic heart disease was present in 24% of naturally infected baboons. Since most non-human primates, irrespective of their serology, have diffuse, nonspecific ECG changes not necessarily diagnostic of myocardial disease, two-dimensional echo should be added to their non-invasive assessment.