Right ventricular free wall strain and effect of implantable defibrillator in non-ischemic heart failure

Abstract

Abstract Background Patients with left ventricular systolic heart failure have a significantly increased risk of all-cause mortality and sudden cardiac death. A cardiac magnetic resonance (CMR) sub-study of the Danish Study to Assess the Efficacy of Implantable Cardioverter Defibrillators (ICDs) in Patients with Nonischemic Systolic Heart Failure on Mortality (DANISH) trial found that in patients who also had reduced right ventricular ejection fraction, ICD implantation significantly increased survival. Recent studies have found that right ventricular free wall strain (RV-FWS) assessed by echocardiography has a similar prognostic power as right ventricular ejection fraction assessed by CMR and RV-FWS determined by echocardiographic may be a more accessible imaging modality to identify patients more likely to benefit from ICD implantation. Purpose To investigate if echocardiographic RV-FWS is related to risk of all-cause death in patients with heart failure and left ventricular systolic dysfunction and whether RV-FWS can identify a sub-group of patients more likely to benefit from ICD implantation. Methods RV-FWS was measured in 343 patients with left ventricular systolic heart failure included in the DANISH trial at our hospital, who underwent an echocardiographic examination before randomization. Cox regression was used to assess the effects of RV-FWS and ICD implantation on all-cause mortality. Impaired RV-FWS was defined as RV-FWS >−20% according to guidelines. Results Median RV-FWS was −19% (quartiles: −24% to −14%). Impaired RV-FWS was present in 186 (54%) patients, and 70 (20.4%) patients died. RV-FWS was related to all-cause mortality both univariably, hazard ratio (HR) 1.07 (95% confidence interval [CI], 1.03–1.11), P=0.001, and adjusted for age, gender, tricuspid annular plane systolic excursion and left ventricular ejection fraction, HR 1.06 (95% CI 1.01–1.10), P=0.009. There was a significant interaction between impaired RV-FWS and effect of ICD, P for interaction=0.045 and ICD implantation significantly reduced mortality in patients with impaired RV-FWS, HR 0.52 (95% CI 0.28–0.96), P=0.04, but not in patients with normal RV-FWS, HR 1.34 (95% CI 0.64–2.82), P=0.44. Conclusion RV-FWS was independently related to all-cause mortality and associated with effect of ICD implantation. With validation in larger studies, impaired RV-FWS may potentially become a candidate for selecting patients for ICD implantation. Impaired RVFWS and effect of ICD Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Danish Heart Foundation