A 26-year-old immigrant from South America comes to the emergency department with palpitations and lightheadedness. He is found to have ventricular tachycardia, which is terminated by intravenous amiodarone. Echocardiogram shows a dyskinetic and thin left ventricular apex consistent with apical aneurysm. Coronary angiogram shows no coronary artery obstruction. Which of the following is the most likely cause of this patient's condition?

Question

A 26-year-old immigrant from South America comes to the emergency department with palpitations and lightheadedness.  He is found to have ventricular tachycardia, which is terminated by intravenous amiodarone.  Echocardiogram shows a dyskinetic and thin left ventricular apex consistent with apical aneurysm.  Coronary angiogram shows no coronary artery obstruction.  Which of the following is the most likely cause of this patient's condition?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c16c_8d83_8f63_fd401c5c82ee_MD0005_00 This patient most likely has chronic Chagas cardiomyopathy, which is caused by a protozoan infection from Trypanosoma cruzi. The natural history of Chagas disease has 3 distinct phases. The first is an acute phase of mild, nonspecific symptoms with fever or myalgias, followed by an indeterminate phase with serologic or parasitic evidence of T cruzi infection in the absence of signs or symptoms of infection. The final phase is chronic Chagas cardiomyopathy and gastrointestinal disease. Chronic Chagas cardiomyopathy is the leading cause of dilated cardiomyopathy in Central and South America. Patients can remain asymptomatic for several years or develop symptoms of heart failure. Findings of right-sided heart failure (eg, jugular venous distension, ascites, edema) are more pronounced than those of left heart failure (eg, dyspnea, crackles). These patients frequently develop arrhythmias, including sinus node dysfunction, complete heart block, and ventricular tachycardia. Echocardiogram shows varying degrees of biventricular dysfunction, along with left ventricular apical aneurysm, which is considered pathognomonic of Chagas cardiomyopathy. (Choice A) Moderate to heavy alcohol consumption can lead to a dilated cardiomyopathy with global hypokinesis and dilation of left ventricular cavity. Segmental dyskinesis and apical aneurysms are not typically seen in patients with alcoholic cardiomyopathy. (Choice B) Borreliosis or Lyme disease is a tick-borne illness caused by an infection with the spirochete Borrelia burgdorferi. Lyme carditis usually manifests as varying degrees of atrioventricular conduction block. In rare cases, patients can also develop myopericarditis with dilated cardiomyopathy. However, apical aneurysms are not typically seen in patients with Lyme carditis. (Choice C) Giant cell myocarditis is a rare form of idiopathic myocarditis thought to be mediated by an autoimmune process. Depending on severity, the echocardiographic findings in patients with myocarditis can include left ventricular dilation, with segmental and/or global left ventricular systolic dysfunction. (Choice D) Infection with human immunodeficiency virus has been associated with the development of dilated cardiomyopathy. Left ventricular apical aneurysm does not occur in patients with HIV-associated cardiomyopathy. Educational objective: Chagas heart disease, caused by protozoan infection due to Trypanosoma cruzi, is the leading cause of dilated cardiomyopathy in Central and South America. The presence of left ventricular apical aneurysm in the absence of coronary disease is pathognomonic for Chagas cardiomyopathy. Other findings include complete heart block and ventricular tachycardia. References: Chagas disease: an overview of clinical and epidemiological aspects. (http://www.ncbi.nlm.nih.gov/pubmed/23770163)

A 26-Year-Old Immigrant from South America Comes to the Emergency