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

## TL;DR

This study finds that right ventricular and left atrial strain measured by CMR can predict how well patients respond to cardiac resynchronization therapy.

## Contribution

The study introduces CMR-derived strain parameters as novel predictors of volumetric response to CRT.

## Key findings

- CRT responders had significantly lower indexed right ventricular volumes and left atrial area compared to non-responders.
- Left atrial and right ventricular strain parameters were significantly better in CRT responders.
- CMR-derived peak septal circumferential strain and RVEDVi correlated with volumetric response to CRT.

## Abstract

Background: While left-bundle-branch-block-related contraction patterns as well as echocardiography-derived strain are variably associated with the volumetric response to cardiac resynchronization therapy (CRT), the role of CMR-derived strain parameters is unexplored. Methods: A total of 50 patients receiving CRT implantation were retrospectively analyzed, all of whom 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 the echocardiographic response, defined as a reduction in the left ventricular end-systolic volume of ≥15%. Results: Among the standard CMR parameters, the indexed right ventricular volumes in end-diastole (RVEDVi) (74.5 ± 19.5 vs. 94.8 ± 30.2 mL/m2, p = 0.006) and end-systole (RVESVi) (43.2 ± 13.3 vs. 61.6 ± 28.8 mL/m2, p = 0.003), as well as the left atrial (LA) area (24.8 ± 3.5 vs. 30.4 ± 9.5 cm2, p = 0.020), differed significantly between CRT responders and non-responders. In strain analysis, CRT responders showed a significantly better LA global longitudinal strain (GLS) (25.1 ± 10.4 vs. 15.3 ± 10.5, p = 0.002), LA global circumferential strain (GCS) (27.9 ± 14.7 vs. 17.1 ± 13.1%, p = 0.012), RV GLS (−25.0 ± 6.5 vs. −18.9 ± 7.6%, p = 0.004) and RV free wall strain (−31.1 ± 7.9 vs. −24.9 ± 9.5, p = 0.017). Conclusions: CMR-derived peak septal circumferential strain and RVEDVi correlated with the echocardiographic volumetric response to CRT at 6–12 months.