A 32-year-old man with known hypertrophic cardiomyopathy is brought to the emergency department after an episode of syncope. He was carrying groceries to his car when he suddenly passed out. He had no chest pain, lightheadedness, nausea, or palpitations prior to the event. The patient now says he feels fine and wants to go home. He was diagnosed with hypertrophic cardiomyopathy 2 years ago. He had a mild provokable left ventricular outflow tract gradient with exercise due to systolic anterior motion of the mitral valve. The gradient was eliminated with metoprolol. The patient claims compliance with the therapy and has no exertional shortness of breath or chest pain. His paternal uncle died suddenly at age 40.
Blood pressure is 132/80 mm Hg and pulse is 62/min. Fourth heart sound is heard at the apex with the patient in the left lateral decubitus position.
Electrocardiogram shows normal sinus rhythm and T-wave inversion in leads I, V5, and V6; it is unchanged from a previous reading.
Which of the following is the best next step in management of this patient?

Question

A 32-year-old man with known hypertrophic cardiomyopathy is brought to the emergency department after an episode of syncope.  He was carrying groceries to his car when he suddenly passed out.  He had no chest pain, lightheadedness, nausea, or palpitations prior to the event.  The patient now says he feels fine and wants to go home.  He was diagnosed with hypertrophic cardiomyopathy 2 years ago.  He had a mild provokable left ventricular outflow tract gradient with exercise due to systolic anterior motion of the mitral valve.  The gradient was eliminated with metoprolol.  The patient claims compliance with the therapy and has no exertional shortness of breath or chest pain.  His paternal uncle died suddenly at age 40.
Blood pressure is 132/80 mm Hg and pulse is 62/min.  Fourth heart sound is heard at the apex with the patient in the left lateral decubitus position.
Electrocardiogram shows normal sinus rhythm and T-wave inversion in leads I, V5, and V6; it is unchanged from a previous reading.
Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Hypertrophic cardiomyopathy (HCM) is a relatively common autosomal dominant genetic cardiac disease with a prevalence of 1:500 in the general population. It has heterogeneous and variable clinical presentation, prognosis, and treatment strategies. Most patients with HCM have few or no symptoms and a normal life expectancy. Sudden cardiac death (SCD) is the most dreaded complication, with an annual incidence of approximately 1% of HCM patients. The following features confer a higher risk of SCD in patients with HCM: History of cardiac arrest (or sustained spontaneous ventricular tachycardia) Family history of sudden death Syncope (recurrent and/or associated with exertion) Nonsustained ventricular tachycardia on Holter monitoring Hypotensive blood pressure response to exercise Extreme left ventricular hypertrophy (>3 cm maximum septal wall thickness) History of cardiac arrest (or sustained spontaneous ventricular tachycardia) Family history of sudden death Syncope (recurrent and/or associated with exertion) Nonsustained ventricular tachycardia on Holter monitoring Hypotensive blood pressure response to exercise Extreme left ventricular hypertrophy (>3 cm maximum septal wall thickness) An implantable cardioverter-defibrillator (ICD) is indicated for both primary and secondary prevention of SCD in patients with >1 major high-risk features. This patient has a history of syncope and a family history of sudden death and should be referred for ICD placement for primary prevention of SCD. (Choice A) Disopyramide is a negative inotropic agent that can be used to alleviate left ventricular outflow tract (LVOT) gradient in patients with symptomatic obstructive HCM. It has no role in primary prevention of SCD. This patient had mild LVOT gradient on exercise that was eliminated with the use of metoprolol. There is no indication for additional therapy with disopyramide at this time. (Choice B) Electrophysiology testing has not been shown to be a reliable predictor of SCD in patients with HCM. It should not be used for risk stratification prior to ICD therapy. (Choice D) Therapy with beta blockers is indicated in symptomatic patients with heart failure and/or LVOT obstruction. This patient had effective reduction in gradient with metoprolol, and additional therapy with metoprolol is not indicated given his heart rate of 62/min. (Choice E) Tilt-table testing is indicated in patients with recurrent episodes of syncope in the absence of organic heart disease. This patient has a known history of HCM with high-risk features and should have an ICD placed for primary prevention of SCD. Educational objective: The major high-risk features that increase risk of sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy include family history of sudden death, recurrent or exertional syncope, nonsustained ventricular tachycardia on Holter monitoring, hypotensive response during exercise, and massive left ventricular hypertrophy >3 cm. Patients with >1 high-risk features should have an implantable cardioverter-defibrillator for the primary prevention of SCD. __________ References: Sudden death in hypertrophic cardiomyopathy: identification of high risk patients. (http://www.ncbi.nlm.nih.gov/pubmed/11127463) 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/22068434)

A 32-Year-Old Man with Known Hypertrophic Cardiomyopathy Is Brought to the Emergency