Chapter 5

A systematic search of the medical literature was performed on April 1, 2008. The search, limited to human subjects and English language journals, included the National Guideline Clearinghouse, the Cochrane database, PubMed, UpToDate®, and PIER. The current American College of Cardiology/European Society of Cardiology Clinical Expert Consensus Document for Hypertrophic Cardiomyopathy can be found at www.acc.org

Hypertrophic cardiomyopathy (HCM) is a complex cardiac disease that can manifest in multiple ways and can occur in patients of all ages.1 The prevalence of HCM is much higher than what was previously thought and it occurs in one out of 500 people. It is now recognized that a gene mutation is responsible for HCM and that it is the most common genetic cardiovascular disease. Many people with HCM are asymptomatic and their lives are not affected by HCM. Others may experience severe limitations in their daily lives and some will have sudden cardiac death (SCD) at an early age. Therefore, it is important for primary care providers to recognize this common cardiac condition and to provide proper management options.

Symptoms of HCM can manifest at any phase of a person’s life; many of these people have relatives with known HCM. Symptoms do not always correlate to the severity of the left ventricular (LV) outflow tract obstruction. Dyspnea on exertion occurs in almost 90% of the symptomatic patients, usually in the presence of preserved systolic function.2 This is due to the increased stiffness of the LV wall leading to elevated LV diastolic and left atrial pressures. Other symptoms range from fatigue to near-syncope or syncope. Typical or atypical chest pain can occur in patients with a normal coronary arteriogram. This may reflect microvascular angina. Unfortunately, the first manifestation of HCM can be sudden death occurring in children or young adults after strenuous physical activity.

Atrial fibrillation (AF) occurs late in the disease process and is generally poorly tolerated. Patients with a stiff, noncompliant left ventricle need the atrial contribution for adequate ventricular filling during diastole. AF in patients with HCM increases the risk for systemic embolization.

In asymptomatic patients with HCM, the physical examination may be normal or may provide nonspecific findings such as a fourth heart sound (some specific recommendations are mentioned in Table 5-1). However, as the outflow obstruction increases, several characteristic abnormalities can be elicited (Fig. 5-1). High-grade obstruction creates a harsh crescendo–decrescendo systolic murmur at the lower left sternal border and apex. The murmur may radiate to the axilla and base, but usually not to the neck. It begins just after S1 and usually represents aortic outflow obstruction often with mitral regurgitation. A prominent S4 is usually present unless the patient is in AF.

Table 5-1. Specific Recommendations3

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