Cardiac Arrhythmias and Conduction Disorders as the Main Manifestation of Chagas Myocarditis

Introduction. Chagas disease is an infectious vector — borne disease caused by the protozoa Trypanosoma cruzi. The main manifestation of the chronic course of Chagas disease is myocarditis, which leads to chamber dilation, congestive heart failure, and cardiac rhythm and conduction disorders. Diagnosis of latent and chronic stages due to low levels of parasitemia is mainly serological. Aim. To study the nature of cardiac arrhythmias and conduction disorders in patients with Chagas myocarditis. Materials and methods. Resting ECG data from 13 patients with chronic Chagas disease aged 28 to 56 years with Chagas myocarditis were analyzed. The etiological factor was confirmed by solid-­phase and recombinant ELISA, exceeding the upper limit of the norm by 2–5 times. Myocarditis was diagnosed by a decrease in the left ventricular ejection fraction below 40% and dilation of the chambers. Results. 8 patients had a stable sinus rhythm, 3 had a permanent form of atrial fibrillation (AF), one had an intermittent form of AF, and 1 patient had a lower atrial rhythm. All 13 people had bradysystole — min heart rate 32 in 1 min, max 46 in 1 min (cf. 41.4 ± 4.3 in 1 min). One patient had a blockage of the antero-superior branch of the left bundle of His, three had a complete right bundle branch block, and one had a combination of antero-superior hemi-block and complete right bundle branch block. 5 patients had a complete grade 3 AV block, two of whom had Frederick’s syndrome. Conclusion. The nature of cardiac arrhythmias in Chagas disease corresponds to those in myocarditis and other etiologies, however, the severity of the registered changes allows us to regard this as a severe course, which is much less common in viral myocarditis. All the examined patients have bradysystolic AF and sinus bradycardia, some of them require constant electrocardiostimulation.