Simultaneous occurrence of hypertrophic obstructive cardiomyopathy and long-QT syndrome: a potentially malignant association

Hypertrophic obstructive cardiomyopathy (HOCM) and long-QT syndrome (LQTS) are cardiac diseases with known genetic disorders. They are inherited in an autosomal-dominant way. From a clinical point of view, both diseases share a disturbed repolarization and the risk of sudden cardiac death. In 1998, during the annual meeting of the German Cardiac Society, we presented the case report of two patients (mother and daughter) with the combination of both diseases, being the first scientific communication on this subject. Both patients experienced sudden cardiac death due to ventricular fibrillation more than 10 years after the first diagnosis of the diseases. Resuscitation resulted in an apallic syndrome in both. The mother died from complications during the course of the apallic syndrome. In contrast to actual therapeutic strategies and data on prophylactic ICD-implantation available today, the daughter received no defibrillator. Sudden death in the presented cases may be due to either disease or their possible malignant association. Thus, the combination of both diseases forms the argument for early prophylactic ICD-implantation in these rare cases. Moleculargenetic studies are needed in large families to elucidate the potential of a common etiology.