Hypertrophic cardiomyopathy (HCM) is one of the more common hereditary cardiac conditions. According to presence or absence of outflow obstruction at rest or with provocation, a more common (about 60–70%) obstructive type of the disease (HOCM) has to be distinguished from the less common (30–40%) nonobstructive phenotype (HNCM). Symptoms include exercise limitation due to dyspnea, angina pectoris, palpitations, or dizziness; occasionally syncope or sudden cardiac death occurs. Correct diagnosis and risk stratification with respect to prophylactic ICD implantation are essential in HCM patient management. Drug therapy in symptomatic patients can be characterized as treatment of heart failure with preserved ejection fraction (HFpEF) in HNCM, while symptoms and the obstructive gradient in HOCM can be addressed with beta-blockers, disopyramide, or verapamil. After a short overview on etiology, natural history, and diagnostics in hypertrophic cardiomyopathy, this paper reviews the current treatment options for HOCM with a special focus on percutaneous septal ablation. Literature data and the own series of about 600 cases are discussed, suggesting a largely comparable outcome with respect to procedural mortality, clinical efficacy, and long-term outcome. 1. Etiology, Pathogenesis, and Pathophysiology of HCM Hypertrophic cardiomyopathy (HCM [1–70]) is a cardiac condition morphologically characterized by unexplained myocardial hypertrophy. Extent and distribution of wall thickening are highly variable; the interventricular septum is most often involved, while the right ventricle is rarely affected. The prevalence of the disease is considered to be around 0.2%; in >50% of patients HCM has a familiar background [3, 6–8]. Inheritance shows an autosomal-dominant pattern, with an incomplete and highly variable penetrance. Mutations have been found in >2 dozens of genes coding for sarcomeric proteins or those involved in myocardial energy metabolism; the condition therefore has been characterized as a “sarcomeric disease” [42–48]. Histologically, the prominent findings in HCM are myocardial disarray, hypertrophy, and fibrosis [49–59]. Not only the myocardial walls but also the coronary vasculature walls are often thickened which may decrease coronary reserve and lead to myocardial ischemia in the absence of occlusive atherosclerosis. In addition, myocardial bridging is a rather frequent finding, and mitral valve leaflets may be elongated [13–15]. Left ventricular systolic function as expressed by the ejection fraction is normal in the vast majority of patients,
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