Review Question - QID 107609

This patient has early-stage chronic Chagas disease. She is suffering from cardiac sequelae of the parasitic infection. Specifically, her EKG shows a right bundle branch block (RBBB), which manifests on her physical exam as a widely split S2 heart sound.

Chagas disease is caused by the parasite Trypanosoma cruzi and is seen in patients who are from or have visited South America. The disease can be classified into three stages: acute, indeterminate, and chronic. Cardiac manifestations can present in the acute phase or may indicate progression of the disease from an indeterminate to chronic phase. Conduction abnormalities (e.g. right bundle branch block) are seen early in the chronic phase and may present with a widely split S2 heart sound.

Woodhall et al. discuss Chagas disease epidemiology, diagnosis, and treatment. Chagas disease is seen in Latin American immigrants and, if left untreated, can lead to death, most commonly via heart failure. Acute parasitemia may present with non-specific febrile illness and should be treated with nifurtimox or benznidazole. Treatment in chronic Chagas disease is only recommended for patients younger than 50 years old without advanced cardiomyopathy.

Bern et al. review chronic cardiac complications of Chagas disease. Years or decades after initial infection, patients may start to exhibit cardiac abnormalities such as conduction defects. Over time, cardiac disease can progress to congestive heart failure and dilated cardiomyopathy. Patients may also suffer from strokes due to thrombus formation in dilated ventricles.

Figure A demonstrates an ECG with a right bundle branch block. Note the RSR' pattern in V1, consistent with RBBB.

Incorrect Answers:
Answer 1: Hypothyroid cardiomyopathy is unlikely, as this patient does not have any other clinical signs or symptoms of hypothyroidism.
Answer 2: Myocarditis would likely be symptomatic and present with heart failure with or without systemic illness.
Answer 4: Hypertensive cardiomyopathy leading to conduction abnormalities is unlikely, as this patient is young and does not have hypertension.
Answer 5: Myocardial infarction is unlikely, as this patient does not have risk factors, signs, or symptoms associated with this condition.