Contractile persistence in apical hypertrophic cardiomyopathy: Definitely too much of a good thing

Hypertrophic cardiomyopathy (HCM) is an atypical condition in the spectrum of cardiovascular diseases. The medical community instinctively equates cardiac disease with impaired contractile force and reduction in myocardial strength, epitomized by the final common pathway of dilated cardiomyopathy and systolic heart failure. In HCM, clinical evaluation and experimental evidence show the opposite. Whether by direct increase in myosin activity (caused by MHY7 mutations) or a decreased inhibitory effect of myosin binding protein C on myosin itself (caused by MYBPC mutations), HCM-causing gene defects result in myocardial hypercontractility.