Role of Right Ventricular Global Longitudinal Strain in Predicting Early and Long-Term Mortality in Cardiac Resynchronization Therapy Patients

BACKGROUND: Right ventricular (RV) dysfunction has been associated with poor prognosis in chronic heart failure (HF). However, less data is available about the role of RV dysfunction in patients with cardiac resynchronization therapy (CRT). We aimed to investigate if RV dysfunction would predict outcome in CRT. DESIGN: We enrolled prospectively ninety-three consecutive HF patients in this single center observational study. All patients underwent clinical evaluation and echocardiography before CRT and 6 months after implantation. We assessed RV geometry and function by using speckle tracking imaging and calculated strain parameters. We performed multivariable Cox regression models to test mortality at 6 months and at 24 months. RESULTS: RV dysfunction, characterized by decreased RVGLS (RV global longitudinal strain) [10.2 (7.0-12.8) vs. 19.5 (15.0-23.9) %, p<0.0001] and RVFWS (RV free wall strain) [15.6 (10.0-19.3) vs. 17.4 (10.5-22.2) %, p = 0.04], improved 6 months after CRT implantation. Increasing baseline RVGLS and RVFWS predicted survival independent of other parameters at 6 months [hazard ratio (HR) = 0.37 (0.15-0.90), p = 0.02 and HR = 0.42 (0.19-0.89), p = 0.02; per 1 standard deviation increase, respectively]. RVGLS proved to be a significant independent predictor of mortality at 24 months [HR = 0.53 (0.32-0.86), p = 0.01], and RVFWS showed a strong tendency [HR = 0.64 (0.40-1.00), p = 0.05]. The 24-month survival was significantly impaired in patients with RVGLS below 10.04% before CRT implantation [area under the curve = 0.72 (0.60-0.84), p = 0.002, log-rank p = 0.0008; HR = 5.23 (1.76-15.48), p = 0.003]. CONCLUSIONS: Our findings indicate that baseline RV dysfunction is associated with poor short-term and long-term prognosis after CRT implantation.