Right ventricular involvement in hypertrophic cardiomyopathy: Patterns and implications

Although hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy worldwide, the criteria for its definition and most of the literature concern the left ventricle, thus confirming the theory that the right ventricle is the neglected one. Right ventricular (RV) involvement includes structural and functional changes with significant impact on clinical presentation and prognosis. The pattern of RV hypertrophy can be variable with possible dynamic obstruction. Histological findings suggest similar pathogenetic changes in both ventricles supporting the common myopathic process with sarcomeric mutations. Systolic dysfunction of the RV is subtle, and the classical echocardiographic indices are usually within normal limits, while global longitudinal strain is significantly impaired. Diastolic dysfunction of the RV is also evident in patients with HCM possibly due to fibrosis of the RV free wall and/or the obstruction of the RV filling with significant prognostic implications. RV involvement in HCM is associated with increased incidence of supraventricular and ventricular arrhythmias, severe dyspnea, pulmonary thromboembolism, progressive heart failure, and increased risk of sudden cardiac death. Therefore, the RV should be routinely included in the detailed assessment of patients with HCM.