A 22-year-old African American man is evaluated for an abnormal ECG obtained at a health fair. He has no complaints and says that he has been healthy all his life. He runs 6-8 miles a day and plays basketball for several hours every weekend. The patient has no symptoms during physical activity. His paternal uncle suffered from diabetes mellitus and died of a heart attack at age 50. His mother had a minor stroke at age 40.
Examination shows a muscular, well-built man. His blood pressure is 132/90 mm Hg on the right arm and 137/85 mm Hg on the left. His pulse is 54/min. Lungs are clear on auscultation, he has normal first and second heart sounds, and peripheral pulses are full and symmetric.
ECG shows high voltage in precordial leads and downsloping ST-segment depression with T-wave inversion in leads V4-V6. An echocardiogram shows left ventricular hypertrophy with septal thickness of 18 mm and posterior wall thickness of 12 mm (normal ≤10 mm). There is no valvular disease, systolic anterior motion of the mitral valve, or left ventricular outflow tract gradient at rest or with Valsalva maneuver.
Which of the following is the most likely diagnosis?

Question

A 22-year-old African American man is evaluated for an abnormal ECG obtained at a health fair.  He has no complaints and says that he has been healthy all his life.  He runs 6-8 miles a day and plays basketball for several hours every weekend.  The patient has no symptoms during physical activity.  His paternal uncle suffered from diabetes mellitus and died of a heart attack at age 50.  His mother had a minor stroke at age 40.
Examination shows a muscular, well-built man.  His blood pressure is 132/90 mm Hg on the right arm and 137/85 mm Hg on the left.  His pulse is 54/min.  Lungs are clear on auscultation, he has normal first and second heart sounds, and peripheral pulses are full and symmetric.
ECG shows high voltage in precordial leads and downsloping ST-segment depression with T-wave inversion in leads V4-V6.  An echocardiogram shows left ventricular hypertrophy with septal thickness of 18 mm and posterior wall thickness of 12 mm (normal ≤10 mm).  There is no valvular disease, systolic anterior motion of the mitral valve, or left ventricular outflow tract gradient at rest or with Valsalva maneuver.
Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec193a_9752_b4d6_853d_eb4448096895_MD0002_00 The most likely diagnosis in this patient is hypertrophic cardiomyopathy (HCM), an autosomal dominant genetic disease. Depending on the degree of hypertrophy and left ventricular outflow obstruction, patients with HCM may have no symptoms at all or severe symptoms (eg, dyspnea, fatigue, chest pain, palpitations, and syncope). HCM must be distinguished from other causes of left ventricular hypertrophy (LVH). The diagnosis of HCM is generally suspected by evidence of LVH on ECG and confirmed by echocardiography. ECG often shows prominent Q waves in inferior and lateral leads, representing septal depolarization. The diagnostic criterion of HCM is LV wall thickness of ≥15 mm (anywhere in the LV wall) that is not readily explained by another cause (eg, hypertension and aortic stenosis). The degree and distribution of hypertrophy in HCM can be quite variable and include asymmetric septal, apical, left ventricular free wall, or concentric hypertrophy. This patient's LV septal wall thickness of 18 mm is consistent with HCM (regardless of the posterior wall thickness of 12 mm). (Choice A) Athlete's heart is a term describing the physiologic increase in left ventricular wall thickness, cavity size, and mass that occurs in response to intense endurance training or exercise. In athlete's heart, LVH is generally symmetric and ≤12 mm. By contrast, in patients with HCM, LVH is frequently asymmetric (as seen in this patient) and wall thickness is ≥15 mm. ECG can show increased QRS voltage in both athlete's heart and HCM; however, Q waves and T wave inversions (as seen in this patient) are more consistent with HCM. Sinus bradycardia at rest is a common feature in well-trained endurance athletes and is due to increased vagal tone induced by exercise conditioning. It will not help differentiate HCM from athlete's heart. (Choice B) Coronary artery anomalies are not associated with LVH. They are usually asymptomatic or can cause exertional angina due to compression of an anomalous coronary artery coursing between the aortic root and main pulmonary trunk. (Choice C) This patient has no history or evidence of severe hypertension. The increase in wall thickness in LVH due to hypertension is generally symmetric and usually <15 mm. (Choice E) Cardiac sarcoidosis commonly presents with conduction abnormalities, including heart block, ventricular arrhythmias, and heart failure, due to systolic or diastolic dysfunction. Severe LVH is not seen with cardiac sarcoidosis. Educational objective: Hypertrophic cardiomyopathy (HCM) is an autosomal dominant genetic disorder characterized by left ventricular hypertrophy (LVH) of variable morphology. In HCM, LVH is frequently asymmetric and wall thickness is ≥15 mm; in individuals with athlete's heart, it is generally symmetric and wall thickness is ≤12 mm. __________ References: Assessment of left ventricular hypertrophy in a trained athlete: differential diagnosis of physiologic athlete's heart from pathologic hypertrophy. (http://www.ncbi.nlm.nih.gov/pubmed/22386289)

A 22-Year-Old African American Man Is Evaluated for an Abnormal