TY - CHAP M1 - Book, Section TI - Alcohol Septal Ablation in Drug-Refractory Obstructive Hypertrophic Cardiomyopathy A1 - Douglas, Jr., John S. A2 - Samady, Habib A2 - Fearon, William F. A2 - Yeung, Alan C. A2 - King III, Spencer B. PY - 2017 T2 - Interventional Cardiology, 2e AB - Hypertrophic cardiomyopathy (HCM), defined clinically by the presence of hypertrophy of a nondilated left ventricle without loading conditions or other recognized causes of hypertrophy, occurs in 1 per 500 individuals in the general population, with approximately 700,000 cases in the US population.1 HCM, inherited with an autosomal dominant Mendelian pattern, is the most common familial heart disease and the most common cause of sudden death in athletes and adolescents. HCM is caused by 1 of more than 1500 different mutations of genes encoding sarcomeric proteins. This genetic heterogeneity and the diverse and unpredictable phenotypic expressions, clinical manifestations, and prognosis limit the value of genetic testing or projections based on affected family members. The vast majority of individuals who are genotype positive/phenotype positive are asymptomatic or minimally symptomatic and are undiagnosed. Heart failure is the most common clinical presentation of HCM in adults. Diagnosis may be difficult due to compensating adjustments in lifestyle that minimize symptoms and nonspecific physical and electrocardiogram (ECG) findings. Elevation of left atrial pressure results from diastolic dysfunction and mitral regurgitation. Limitations of cardiac output in HCM resulting in fatigue, dyspnea, presyncope, and syncope are commonly related to left ventricular outflow tract (LVOT) obstruction and low end-diastolic volume because of diastolic dysfunction. LVOT obstruction (LVOT pressure gradient ≥30 mm Hg) is present in one-third of HCM patients at rest and in an additional one-third with provocation with Valsalva maneuver, nitroglycerin, post-extrasystolic potentiation, or exercise echocardiography, a preferred method of evaluating patients with no resting LVOT gradient but marked exercise tolerance. The presence of LVOT obstruction is a predictor of HCM-related progressive heart failure and heart failure death,2 and relief of obstruction surgically results in better survival than achieved by patients without this treatment.3 Relief of LVOT obstruction is a principle goal of both medical and septal reduction therapies. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - accesscardiology.mhmedical.com/content.aspx?aid=1146604306 ER -