Electrophysiologic findings in long-term asymptomatic chagasic individuals.

Under electrophysiologic studies, 44 asymptomatic chagasic individuals were studied. The mean age was 39.9 years, with 26 being male. The surface ECG showed normal tracings in 12 patients, left anterior fascicular block in three, incomplete right bundle branch block in two, and right bundle branch block in 27 (isolated in six, associated with left anterior fascicular block in 19 and with left posterior fascicular block in two). Sinus nodal dysfunction was found in eight (18.1%), and 29 (66%) presented with some form of abnormal AV nodal behavior during atrial stimulation. Repetitive ventricular beats were recorded in 17 (41.4%) patients. Finally, in 19 (43.1%), patterns of dysfunction at two or more levels of the cardiac conducting system were found. It is concluded that the chagasic cardiomyopathy produces diffuse lesions in the conducting tissue of the human heart in the stages when the disease is detected, and that the individuals are still asymptomatic.