Long-term follow-up of cardiac resynchronization therapy patients with non-ischemic dilated cardiomyopathy assessed by radionuclide angiography

Abstract

Abstract Background While the beneficial effects of cardiac resynchronization therapy (CRT) have been widely investigated soon after CRT implantation, relatively few data are available on long-term clinical outcomes of CRT recipients. Aim To investigate long-term outcomes of CRT patients with non-ischemic dilated cardiomyopathy stratified as responders and non-responders according to radionuclide angiography. Methods Consecutive heart failure patients with non-ischemic dilated cardiomyopathy undergoing CRT implantation at our University Hospital between 2007 and 2013 were enrolled. All patients were assessed with equilibrium Tc99 radionuclide angiography at baseline and after 3 months of CRT. Left ventricular (LV) ejection fraction was computed on the basis of relative end-diastolic and end-systolic counts, and intraventricular dyssynchrony was derived by Fourier phase analysis. Response to CRT was defined by an absolute increase in LV ejection fraction (LVEF) ≥5% at 3-month follow-up. Clinical outcome was assessed after 10 years through hospital records review. Results Forty-seven patients (83% men, 63±11 years) were included in the study. At 3 months, 25 (53%) patients were identified as CRT responders according to LVEF increase (from 26±8 to 38±12%, p<0.001). In these patients, LV dyssynchrony decreased from 59±30° to 29±18° (p<0.001). Twenty-two (47%) patients were defined as non-responders. No significant changes in LVEF and LV dyssynchrony (50±30° vs. 38±19°, p=0.07) were observed in non-responders. At long-term follow-up (11±2 years), all-cause and cardiac mortality rates were 24% and 12% in responders vs. 32% and 27% in non-responders, respectively (p=ns). Heart transplantation was performed in 3 patients. One (4%) patient among CRT responders compared with 6 (27%) patients among non-responders died of worsening heart failure (p=0.03). Conclusions Although late overall mortality of non-ischemic CRT recipients was not significantly different between mid-term responders and non-responders, CRT responders were at lower risk of worsening heart failure death. Funding Acknowledgement Type of funding source: None