Right atrial reservoir strain: a novel and strong predictor of long-term survival after cardiac resynchronization therapy

Abstract Background Left atrial (LA) reservoir strain is established both as index of elevated left ventricular (LV) filling pressures and as prognostic marker in various cardiac diseases. The clinical utility of right atrial (RA) strain, however, remains largely unexplored. Since tissue congestion in peripheral organs is an independent predictor of mortality in congestive heart failure, we hypothesized that RA reservoir strain, due to its association with RA pressure and central venous pressure is a prognostic marker in heart failure. Purpose To investigate the association between RA reservoir strain and long-term survival after cardiac resynchronization therapy (CRT). Methods In a prospective multicenter study of 100 patients undergoing CRT, RA reservoir strain was assessed by speckle-tracking echocardiography before and 7 ± 1 months post-implantation. RA reservoir strain was defined as the difference between peak and minimum global strain during the atrial cycle (Figure 1). The optimal cutoff for prognostication (22%) was determined using the Youden index from a receiver operating characteristic curve (upper panel in Figure 2). All-cause mortality was the clinical endpoint. Survival analysis was performed using Kaplan–Meier curves, and multivariable predictors were assessed by Cox regression analysis. Results Over a mean follow-up of 5.9 ± 1.0 years, 25 patients (25%) died. At follow-up, RA reservoir strain was significantly higher in survivors compared to non-survivors (24 ± 10% vs 15 ± 6%, P < 0.001). RA reservoir strain after CRT demonstrated good discriminatory ability for all-cause mortality (AUC = 0.77, 95% CI: 0.68–0.87, P < 0.001; upper panel, Figure 2). Patients with RA reservoir strain ≥22% had significantly better survival than those below this threshold (HR 0.21, 95% CI: 0.10–0.46, P < 0.001; lower panel, Figure 2). In multivariable Cox regression adjusting for heart failure etiology and QRS duration and morphology assessed before CRT, as well as change in LV end-systolic volume ≥15%, LV global longitudinal strain, LA reservoir strain, and RA reservoir strain assessed after CRT, RA reservoir strain remained an independent predictor of survival (Exp(B) = 0.91, 95% CI: 0.84–0.98, P = 0.013) Conclusions In a heart failure population undergoing CRT, RA reservoir strain ≥22% after CRT was an independent predictor of favorable long-term survival. These findings suggest a potential role for RA strain as a novel marker of long-term prognosis in heart failure. Future studies should further explore its clinical utility.Right atrial strain measurement  Right atrial strain and survival