Right Ventricular and Left Atrial Strain Predict Volumetric Response to Cardiac Resynchronization Therapy

Background: While left-bundle-branch-block-related contraction patterns as well as echocardiography derived strain are variably associated with volumetric response to cardiac resynchronization therapy (CRT), the role of CMR-derived strain parameters is unexplored. Methods: 50 patients receiving CRT implantation were retrospectively analysed, all of which had undergone CMR imaging within one year before, and echocardiography within 6 months before and 6-12 months after CRT implantation. We assessed CMR-derived morphological and functional parameters with regard to echocardiographic response, defined as reduction of left ventricular end-systolic volume ≥15%. Results: Among standard CMR parameters, indexed right ventricular volumes in end-diastole (RVEDVi) (74.5 ±19.5 vs. 94.8 ±30.2 ml/m², P=.006) and end-systole (RVESVi) (43.2 ±13.3 vs. 61.6 ±28.8 ml/m², P=.003) as well as left atrial (LA) area (24.8 ±3.5 vs. 30.4 ±9.5 cm², P=.020) differed significantly between CRT responders and non-responders. In strain analysis, CRT responders showed significantly better LA global longitudinal strain (GLS) (25.1 ±10.4 vs. 15.3 ±10.5, P=.002), LA global circumferential strain (GCS) (27.9 ±14.7 vs. 17.1 ±13.1%, P=.012), RV GLS (-25.0 ±6.5 vs. -18.9 ±7.6%, P=.004) and RV free wall strain (-31.1 ±7.9 vs. -24.9 ±9.5, P=.017). Conclusions: CMR-derived peak septal circumferential strain and RVEDVi correlated with echocardiographic volumetric response to CRT at 6-12 months.