Natural History of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a cardiac condition that continues to fascinate clinicians because of the diversity and complexity of its morphologic and functional features. However, despite 30 years of intensive investigation, the natural history of the overall HCM population is not completely understood, and consequently, patient management continues to represent a challenge, A major obstacle to the assessment of prognosis comes from the heterogeneity of the clinical course of the disease; some patients remain asymptomatic throughout life, some develop severe symptoms of heart failure, and others die suddenly and unexpectedly in the absence of previous symptoms. This diverse clinical course has introduced an important bias in the literature on HCM. Patients with severe symptoms or those judged to be at high risk of sudden death traditionally have been referred to tertiary HCM centers; because most of the published studies have come from these centers, the picture of the disease projected in the literature has been based on a small, highly selected portion of the overall patient population. Recent investigations performed in less-selected populations show that the natural history of HCM is benign in many patients, although it has a progressive evolution in some and can result in sudden death in the absence of previous symptoms in a few. Therefore, the challenge with which we are now confronted is to distinguish the many patients who are at low risk and need only reassurance regarding their prognosis from the few who are at high risk of sudden death and require aggressive treatment. In the present discussion, we summarize some general guidelines that address this complex clinical issue.