A 64-year-old female patient sought medical assistance at our hospital due to dyspnea on light exertion and even at rest.The patient had been experiencing dyspnea on strenuous exertion since the age of 52 years, which progressed in 10 years to dyspnea on light exertion and even orthopnea.On physical examination (9/1/97), her pulse was regular, her heart rate was 56bpm, and her blood pressure was 140/170mmHg. Her lung examination was within the normal range. The cardiac ictus could be felt on the left 6 th intercostal space over the length of 2 fingertips. A systolic thrill was palpated on the 6 th intercostal space. The cardiac sounds were normal. A systolic cardiac murmur (++/4) was heard on the mitral area and a diastolic cardiac murmur was heard on the aortic area. The abdominal examination was within the normal range and no edema of the lower limbs was observed.The chest X-ray showed enlargement of the cardiac silhouette (++++/4) and normal pulmonary fields.Electrocardiography (8/27/97) showed an ectopic atrial rhythm, a P-R interval of 0.12 s, an initial disturbance of ventricular depolarization (initial QRS blurring in II, III, aVF, and V2), disorder of heart conduction of the anterosuperior left bundle-branch and the right branch, and alterations in ventricular repolarization ( fig. 1).The laboratory tests (8/27/97) were as follows: hemoglobin, 13.6g/dL; hematocrit, 39%; serum creatinine, 0.7mg/ dL; serum sodium, 141mEq/L; and serum potassium, 4.5mEq/L. The serum tests for Chagas' disease were positive.The diagnosis of heart failure due to Chagas' cardiomyopathy was established and the patient was prescribed 37.5mg of captopril and 25mg of hydrochlorothiazide daily.Echocardiography (12/18/97) showed diffuse hypokinesia of the left ventricle, ectasia of the aortic root, moderate regurgitation of the aortic and mitral valves, and pulmonary hypertension. The measurements are shown in table I.Chest tomography (3/31/99) revealed ectasia of the aortic root (52.66mm) and the following preserved diameters: ascending aorta (39.79mm), aortic arch (31.12mm and 25.76mm), descending aorta (26.27mm), and thoracoabdominal transition (21.4mm).The symptoms subsided, as did the dyspnea on moderate exertion. After 10 months, however, the dyspnea became more severe, being triggered on minimum exertion, and even orthopnea occurred (Sept '98). The patient then sought medical care, and an irregular cardiac rhythm was observed.Electrocardiography (9/3/98) showed an irregular rhythm of the atrial pacemaker with junctional escapes and ventricular premature depolarizations, QRS duration of 0.12 s, anterosuperior left bundle-branch block and block of the right branch ( fig. 2).Two months later, the patient required hospitalization (from 11/17/98 to 12/10/98) for control of heart failure.On physical examination (11/17/98), the patient had an irregular pulse, heart rate of 56 bpm, blood pressure of 110/ 80mmHg, crepitant rales in the base of her thorax, irregular cardiac rhythm due to frequent premature depolarizations, and a systolic...