Right ventricular diastolic dysfunction in patients with left ventricular hypertrophy: Analysis of right ventricular myocardial relaxation using two-dimensional speckle tracking imaging

Background: Although several previous studies have suggested the presence of right ventricular (RV) diastolic dysfunction in patients with hypertrophic cardiomyopathy (HCM) and those with hypertensive left ventricular hypertrophy (HT-LVH), the mechanisms are still unclear. This study aimed to clarify the relationship between the RV global diastolic dysfunction in these patients and the regional myocardial diastolic function, including synchronicity of the interventricular septum and RV free wall. Methods: In 20 age-matched patients with HT-LVH, 20 patients with HCM and 22 control subjects without pulmonary hypertension, RV isovolumic relaxation time (IRT_R) was measured using continuous-wave Doppler echocardiography. The early diastolic peak strain rate (E_SR) and time from QRS to E_SR (T-E_SR) were measured in the apical, mid-ventricular and basal segments of the interventricular septum and RV free wall using two-dimensional speckle tracking imaging (2DST). Results: IRT_R was more prolonged both in HT-LVH and in HCM than in the controls. The averaged septal E_SR was reduced both in HT-LVH and in HCM (P < 0.0001, respectively), but the averaged RV free wall E_SR was decreased only in HCM (P = 0.0007). E_SR averaged for six septal and RV free wall segments was correlated with IRT_R (r = -0.46, P = 0.0001). Neither intergroup difference nor correlation with IRT_R was observed in a coefficient of variation of T-E_SR for the six segments. Conclusions: RV global diastolic function is impaired in patients with HT-LVH and HCM due to relaxation abnormalities, not an asynchrony, of the myocardium surrounding the RV cavity. The detection of RV free wall relaxation abnormality using 2DST may be useful to differentiate HCM from HT-LVH.