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KEY FEATURES

ESSENTIALS OF DIAGNOSIS

  • Remote history of residence in rural Central or South America

  • ECG evidence of conduction system disease, especially right bundle branch block and left anterior fascicular block, and ST-segment elevation suggesting ventricular aneurysm

  • Premature ventricular contractions and nonsustained ventricular tachycardia (VT)

  • Echocardiographic evidence of an apical left ventricular aneurysm

  • Positive serology for Trypanosoma cruzi

GENERAL CONSIDERATIONS

  • Caused by the protozoan T. cruzi

  • Most common cause of cardiomyopathy in South and Central America

  • Three phases of Chagas’ disease: acute, indeterminate, and chronic

  • Pericarditis-myocarditis may develop in the acute phase with variable signs of cardiac failure that often resolve

  • Patients are asymptomatic during the indeterminate phase, which lasts 10–30 years

  • Thirty percent of patients in the indeterminate phase eventually develop chronic heart failure

  • Cardiomyopathy occurs in the chronic phase of T. cruzi infection

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

  • Remote history of residence in South or Central America

  • Fatigue

  • Palpitations

  • Dizziness and syncope

  • Stokes-Adams attacks due to arrhythmias

  • Chest pain

  • Dyspnea

  • Dysphasia in patients with megaesophagus

  • Severe constipation and abdominal discomfort in patients with megacolon

PHYSICAL EXAM FINDINGS

  • Tachypnea

  • Tachycardia

  • Hypotension

  • Elevated jugular venous pressure

  • Pulmonary rales

  • Diffuse, sustained apical impulse

  • Wide splitting of S2 due to right bundle branch block

  • Systolic murmurs of mitral and tricuspid insufficiency

  • S3 and S4

  • Hepatomegaly and pulsatile liver

  • Abdominal ascites

  • Peripheral edema

  • Signs of thromboemboli phenomenon

DIFFERENTIAL DIAGNOSIS

  • Coronary artery disease

  • Dilated cardiomyopathy

  • Isolated conduction system disease

  • Other causes of ventricular arrhythmias

DIAGNOSTIC EVALUATION

LABORATORY TESTS

  • Laboratory findings are nonspecific

  • CBC demonstrates leukocytosis with an absolute increase in lymphocyte count

  • Serologic tests for T. cruzi

ELECTROCARDIOGRAPHY

  • Sinus rhythm or sinus bradycardia

  • Atrial fibrillation

  • VT

  • First- to third-degree atrioventricular (AV) block

  • Right bundle branch block

  • Left anterior fascicular block

IMAGING STUDIES

  • Chest x-ray: variable degrees of cardiomegaly, pulmonary vascular redistribution, and pulmonary edema

  • Echocardiography: variable ventricular dilatation and reduced systolic function; a ventricular apical aneurysm may be present; mural thrombi may be present; mitral and tricuspid regurgitation are often present

DIAGNOSTIC PROCEDURES

  • Cardiac catheterization and angiography: can exclude coronary artery disease

  • Electrophysiologic study: indicated in selected cases to assess sinus node function and AV conduction in symptomatic patients; may be useful in patients with sustained VT to determine prognosis and select the appropriate antiarrhythmic therapy

TREATMENT

CARDIOLOGY REFERRAL

  • Heart failure

  • Arrhythmias

HOSPITALIZATION CRITERIA

  • Decompensated heart failure

  • Syncope

  • Thromboembolic events and stroke

  • Arrhythmias

  • Symptomatic bradycardia

MEDICATIONS

  • Guideline-directed medical therapy for heart ...

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