Evolution of Hypertrophic Cardiomyopathy to a Contemporary Treatable Disease

Case 1: The patient is now a 56-year-old man with nonobstructive hypertrophic cardiomyopathy (HCM). At 35 years of age, his brother (aged 39) died suddenly with a new diagno-sis of HCM made at autopsy. A diag-nostic evaluation ensued, and nonob-structive HCM was identified with a ventricular septal thickness of 31 mm. Because of the family history of sud-den death (and his marked hypertro-phy), an implantable cardioverter- de-fibrillator (ICD) was implanted for primary prevention of sudden death. Five years later, during sleep (1:00 AM), the ICD aborted an episode of ventricular fibrillation (VF) and re-stored sinus rhythm (Figure 1). Nine years passed without incident, and at 50 years of age, an identical VF event occurred during sleep, similarly termi-nated by a defibrillation shock. Now, at 56 years of age, the patient contin-ues to be asymptomatic and active. His clinical course with HCM has been punctuated only by these 2 unpredict-able sudden-death events effectively treated by an ICD prophylactically im-planted for high-risk status. Case 2: The patient is a 53-year-old female elementary school teacher with obstructive HCM. She presented at 44 years of age, asymptomatic, but with a strong family history of sudden deaths due to HCM in 2 brothers (aged 20 and 34 years, respectively). An ICD was implanted prophylactically, and 2 years later (at 46 years of age), VF was defibrillated during sleep. Over the next 6 years, 4 more appropriate inter-ventions for ventricular tachycardia (VT)/VF followed. Ventricular septal thickness is 21 mm; left ventricular outflow obstruction is absent at rest, although provoked with exercise (gradient, 70 mm Hg). By 51 years of age, exertional dyspnea and functional limitation had progressed de-spite maximum medical management, with the patient disabled in New York Heart Association functional class III. Surgical septal myectomy abolished both the outflow gradient and the pa-tient’s heart failure–related symptoms. Once again, at 53 years of age, she is asymptomatic and active, having experi-enced 2 adverse disease pathways, ie, sudden-death risk, and heart failure due to outflow tract obstruction, both of which were amenable to effective treat-ment strategies