Exercise speckle-tracking strain imaging demonstrates impaired right ventricular contractile reserve in hypertrophic cardiomyopathy

Abstract

AimsTo analyse right ventricular (RV) systolic function in patients with hypertrophic cardiomyopathy (HCM) at rest and during exercise, and its possible correlation with left ventricular(LV) morphology and function. Methods and resultsStandard echo, exercise stress echo, and RV 2D speckle-tracking strain (2DSE) were performed in 45 patients with HCM and in 45 age- and sex-comparable healthy controls. RV global longitudinal strain (GLS) was calculated by averaging local strains along the entire right ventricle. LV mass index and IVS wall thickness were significantly increased in HCM, while LV ejection fraction, RV diameters, RV tissue Doppler systolic peak and the RV end-systolic pressure-area relationship at rest were comparable between the two groups. Conversely, all transmitral Doppler indexes were significantly impaired in HCM. In addition, RV GLS and regional peak myocardial RV strains were significantly reduced in patients with HCM (all P<0.001). During physical effort, LV ejection fraction was comparable between the two groups. Conversely, LV E/Em ratio was significantly increased in HCM. Increase in TAPSE and RV tissue Doppler Sm peak velocity during effort were similar between the two groups. Conversely, increases of RV end-systolic pressure-area, regional and global RV strain were significantly lower in HCM patients (RV lateral strain: 10.3±3.5% of increase in HCM vs 20.5±4.5% in controls; p<0.0001). Multivariable analysis detected independent associations of RV lateral strain at peak stress with LV IVS thickness, maximal workload during exercise, and LV E/Em ratio during effort (all p<0.0001). An RV lateral 2DSE cut-off point of −14% differentiated controls and HCM with an 86%sensitivity and a 92% specificity. ConclusionsRV contractile reserve for HCM is impaired and this suggests that the lower resting values of RV in HCM may represent early subclinical myocardial damage, closely associated with exercise capacity.