A 31-year-old man comes to the physician due to exertional shortness of breath over the last year. He gets short of breath after running 1-2 miles but feels mostly fine with daily activities. He has no chest pain, palpitations, or fainting spells. He also has no past medical history and takes no medications. There is no family history of sudden death. His blood pressure is 147/90 mm Hg, pulse is 77/min, and body mass index is 22 kg/m². The apical precordial impulse is hyperdynamic. S1 and S2 are normal and a fourth heart sound is heard. He has a 2/6 systolic murmur at the left sternal border which increases with Valsalva. The lungs are clear to auscultation. An echocardiogram shows interventricular septal thickness of 1.8 cm (normal

Question

A 31-year-old man comes to the physician due to exertional shortness of breath over the last year. He gets short of breath after running 1-2 miles but feels mostly fine with daily activities. He has no chest pain, palpitations, or fainting spells. He also has no past medical history and takes no medications. There is no family history of sudden death. His blood pressure is 147/90 mm Hg, pulse is 77/min, and body mass index is 22 kg/m². The apical precordial impulse is hyperdynamic. S1 and S2 are normal and a fourth heart sound is heard. He has a 2/6 systolic murmur at the left sternal border which increases with Valsalva. The lungs are clear to auscultation. An echocardiogram shows interventricular septal thickness of 1.8 cm (normal <1.1 cm) and posterior left ventricular wall thickness of 0.9 cm (normal <1.1 cm). Left ventricular ejection fraction is 75%. There is systolic anterior motion of the mitral valve. At rest, his peak instantaneous left ventricular outflow gradient is 25 mm Hg; however, it is 65 mm Hg after exercise. Holter monitoring for 24 hours shows no abnormalities. Which of the following is the best next step in the management of this patient?

Quizplus · Accepted Answer

Explanation: This patient's clinical presentation - fatigue, exertional dyspnea, systolic murmur that accentuates with Valsalva, asymmetric septal hypertrophy, systolic anterior motion (SAM) of mitral leaflets, and increased left ventricular outflow tract (LVOT) gradient - is consistent with hypertrophic cardiomyopathy (HCM). HCM is an autosomal dominant genetic disorder of the cardiac sarcomere. It has a heterogeneous and variable clinical presentation depending on the degree of hypertrophy and LVOT obstruction. Patients with HCM may have no symptoms or have severe symptoms of fatigue, dyspnea, chest pain, palpitations, presyncope, or syncope. systolic murmur Patients with symptoms of heart failure and increased LVOT gradient should be treated with negative inotropic agents (beta-blockers, verapamil or disopyramide) as the initial medical therapy. Beta-blockers are the most commonly used agents for initial monotherapy; verapamil or disopyramide can be added to beta-blocker therapy in patients with persistent symptoms. (Choice A) Alcohol septal ablation involves injecting ethanol into the first or second septal perforator artery to cause a localized myocardial infarction in the basal septum. This causes localized scarring and remodeling over time and can lead to a reduction in LVOT gradient with improvement in symptoms and exercise capacity. It is usually reserved for patients with persistent symptoms that are refractory to medical therapy. (Choice B) Amiodarone is not routinely used in the management of patients with HCM. It can be used as an adjunctive therapy in patients who are at risk for sudden cardiac death and are not candidates for implantable cardioverter-defibrillator (ICD), or in patients with ICD who experience frequent arrhythmias. (Choice C) Vasodilators (dihydropyridine calcium channel blockers such as amlodipine and nifedipine), angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers, and nitrates can reduce systemic vascular resistance with worsening of the LVOT gradient and symptoms. These should not be used in patients with HCM. (Choice D) ICD therapy is indicated for primary prevention of sudden cardiac death in patients with >1 major high-risk features or for secondary prevention of sudden cardiac death in patients with a history of cardiac arrest or sustained spontaneous ventricular tachycardia. There is no such indication in this patient. high-risk features Educational objective: Negative inotropic agents (beta-blockers, verapamil or disopyramide) are recommended for the medical management of symptomatic patients with HCM and elevated left ventricular outflow tract gradient. Beta-blockers are preferred as initial therapy, and verapamil or disopyramide can be used as additional therapy in patients with persistent symptoms. References: Hypertrophic cardiomyopathy. (http://www.ncbi.nlm.nih.gov/pubmed/22874472) ß Blockers for prevention of exercise-induced left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy. (http://www.ncbi.nlm.nih.gov/pubmed/22633205)

A 31-Year-Old Man Comes to the Physician Due to Exertional