How should hypertrophic cardiomyopathy be classified?: Molecular diagnosis for hypertrophic cardiomyopathy: Not ready for prime time.

Fifty years ago, Donald Teare,1 a well-known forensic pathologist in London, reported 8 cases of “asymmetrical hypertrophy or benign tumor” of the heart. Each had disproportionate hypertrophy of the interventricular septum, a coarse myocardial texture, and a bizarre arrangement of muscle fibers, separated by excessive connective tissue and clefts. At the time, numerous names for this entity were proposed, but after a relatively short period, the term hypertrophic cardiomyopathy (HCM) was adopted and has remained the accepted nomenclature to this day. In this issue of Circulation: Cardiovascular Genetics, Maron et al2 propose a change to this convention by advocating a much more restrictive use of the term to describe myocardial hypertrophy caused by mutations in genes that encode sarcomere proteins. In our view, the rationale for this proposal is flawed and, following as it does on the tail of 2 recent updates of the cardiomyopathy classification, will result in increased confusion.