Right ventricular involvement in hypertrophic cardiomyopathy: a case report and literature review

Although hypertrophic cardiomyopathy (HCM) is classically considered a disease of the left ventricle, right ventricular (RV) abnormalities have also been reported. However, involvement of the right ventricle in HCM has not been extensively characterized. The literature regarding prevalence, genetics, patterns of involvement, histologic findings, symptoms, diagnosis, and treatment of RV abnormalities in HCM is reviewed. To highlight the salient points, a case is presented of apical HCM with significant RV involvement, with an RV outflow tract gradient and near obliteration of the RV cavity, in the absence of a left intraventricular gradient. Right ventricular involvement in HCM appears to be as heterogeneous as that of the left ventricle. The spectrum extends from mild concentric hypertrophy to more unusual severe, obstructive disease. While in some cases the extent of RV involvement correlates with left ventricular (LV) involvement, predominant RV disease can be seen as well. While the genetics of RV involvement have not been well characterized, histologic findings appear to be similar to those in the left ventricle, suggesting similar pathogenesis. Significant RV involvement may result in RV outflow obstruction and/or reduced RV diastolic filling, with potentially increased incidence of severe dyspnea, supraventricular arrhythmias, and pulmonary thromboembolism. The optimal treatment for patients with significant RV disease is unknown. Medical and surgical therapies have been attempted with variable success; experience with newer techniques such as percutaneous catheter ablation has not been reported. Further characterization of RV involvement in HCM is necessary to elucidate more clearly the clinical features and optimal treatments of this manifestation of HCM.