The patient should be treated by placement of an implantable cardioverter-defibrillator (ICD). He has asymptomatic mild obstructive hypertrophic cardiomyopathy (HCM). An essential goal in the management of patients with HCM is risk stratification and identification of patients who may benefit from therapy with an ICD. Patients should be considered for ICD therapy if they have any of the following risk factors for sudden cardiac death: (1) massive myocardial hypertrophy (wall thickness ≥30 mm); (2) previous cardiac arrest due to ventricular arrhythmia; (3) blunted blood pressure response or hypotension during exercise; (4) unexplained syncope; (5) nonsustained ventricular tachycardia on ambulatory electrocardiography; and (6) family history of sudden death due to HCM. In patients who have ICD placement for secondary prevention of sudden death (that is, patients with prior cardiac arrest due to ventricular arrhythmia), in whom the indications for implantation are most compelling, the rate of appropriate device discharge is approximately 11% per year. For primary prevention, the annual rate of appropriate ICD discharge is approximately 4%. Although older studies from tertiary referral centers suggested an adverse prognosis for all patients with HCM, multiple contemporary investigations from relatively unselected cohorts have shown that HCM is compatible with normal longevity in most patients, particularly those without risk factors for sudden death, with the overall incidence of death ranging from 0.5% to 0.8% per year.

Septal reduction therapy, with either alcohol septal ablation or surgical myectomy, is indicated only for patients with drug-refractory, severe symptoms and not the mild symptoms that this patient has. Survival has been shown to be favorable among selected patients who undergo septal reduction therapy in experienced centers, but neither ablation nor surgical myectomy is advocated as a means of preventing sudden cardiac death.

β-Blocker therapy is reserved principally for patients with symptoms and has not been associated with reduction in risk of sudden cardiac death.