A 24-year-old man comes to the office for an exercise evaluation. He is an avid long-distance runner. One of his team members recently died suddenly in his sleep, which made the patient worried about his health. He has no medical history, takes no medications, and does not use illicit drugs. His maternal grandfather had a heart attack at age 40 and underwent coronary artery bypass surgery. Blood pressure is 122/70 mm Hg and pulse is 49/min. Transthoracic echocardiogram shows the following: The right ventricular cavity is slightly enlarged and there are no valvular lesions. Which of the following best explains this patient's echocardiogram findings?

Question

A 24-year-old man comes to the office for an exercise evaluation.  He is an avid long-distance runner.  One of his team members recently died suddenly in his sleep, which made the patient worried about his health.  He has no medical history, takes no medications, and does not use illicit drugs.  His maternal grandfather had a heart attack at age 40 and underwent coronary artery bypass surgery.  Blood pressure is 122/70 mm Hg and pulse is 49/min.  Transthoracic echocardiogram shows the following:  The right ventricular cavity is slightly enlarged and there are no valvular lesions.  Which of the following best explains this patient's echocardiogram findings?

Quizplus · Accepted Answer

This patient's echocardiogram findings are consistent with athlete's heart (ie, the physiologic cardiac adaptations that occur in highly trained athletes). Endurance exercise (eg, long-distance running) mostly increases the volume load on the heart (increased cardiac output) with a small component of increased pressure load (increased afterload). As a result, the left ventricle predominantly undergoes eccentric hypertrophy (cavity enlargement improves diastolic function) with a small amount of concentric hypertrophy (wall thickening increases systolic function). The right ventricular cavity also slightly enlarges to support an increase in cardiac output, and there is enhanced coronary capillary development and a decreased resting heart rate due to improved efficiency of cardiac pumping. Because these physiologic changes improve cardiac function, athlete's heart is not associated with an increased risk of cardiovascular morbidity or mortality. However, it is imperative that the changes of athlete's heart are differentiated from similar cardiac anomalies that may reflect serious underlying pathology that could increase the risk of sudden cardiac death (eg, hypertrophic cardiomyopathy). Findings that favor the presence of hypertrophic cardiomyopathy (Choice C) include left ventricular (LV) hypertrophy predominantly affecting the septum, LV hypertrophy with reduced LV cavity size, impaired diastolic function, and a poorly developed coronary capillary network. (Choice A) Anabolic steroid abuse can cause pathologic concentric LV hypertrophy, characterized by reduced diastolic function and poor coronary vascularization. (Choice D) Severe coronary artery disease can lead to ischemic cardiomyopathy, which typically manifests as dilated cardiomyopathy with an enlarged LV cavity but thin LV walls with impaired systolic function. (Choice E) Viral myocarditis may sometimes lead to dilated cardiomyopathy with eccentric hypertrophy and impaired LV systolic function. Subclinical disease is typically quite mild and resolves without sequelae. Educational objective: Athlete's heart refers to physiologic cardiac adaptations that improve cardiac function in response to high-level endurance training. There is predominant left ventricular (LV) eccentric hypertrophy with a small component of concentric hypertrophy, leading to an overall increase in LV mass, enlarged LV cavity size, slightly increased LV wall thickness, and decreased resting heart rate. __________ References: Athlete's heart. (http://www.ncbi.nlm.nih.gov/pubmed/14617564) The athlete's heart part I (review). (http://www.ncbi.nlm.nih.gov/pubmed/21138810)

A 24-Year-Old Man Comes to the Office for an Exercise