Baseline QRS Duration Associates with Cardiac Recovery in Patients with Continuous-Flow Left Ventricular Assist Device Implantation

BACKGROUND In chronic heart failure (HF) patients supported with continuous-flow left ventricular assist device (CF-LVAD), we aimed to assess the clinical association of baseline QRS duration (QRSd) with post-LVAD cardiac recovery, and its correlation with pre- to post-LVAD change in left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter (LVEDD). METHODS Chronic HF patients (n=402) undergoing CF-LVAD implantation were prospectively enrolled, at one of the centers comprising the U.T.A.H. (Utah Transplant Affiliated Hospitals) consortium. After excluding patients with acute HF etiologies, hypertrophic or infiltrative cardiomyopathy, and/or inadequate post-LVAD follow up (<3 months), 315 patients were included in the study. Cardiac recovery was defined as LVEF ≥40% and LVEDD <6 cm within 12 months post-LVAD implantation. Patients fulfilling this condition were termed as responders (R) and results were compared with non-responders (NR). RESULTS Thirty-five patients (11%) achieved ‘R’ criteria, and exhibited a 15% shorter QRSd compared to ‘NR’ (123±37 ms vs 145±36 ms; p<0.001). A univariate analysis identified association of baseline QRSd with post-LVAD cardiac recovery (OR:0.986, 95% CI:0.976-0.996, p<0.001). In a multivariate logistic regression model, after adjusting for duration of HF (OR:0.990, 95% CI:0.983-0.997, p=0.006) and gender (OR:0.388, 95% CI:0.160-0.943, p=0.037), pre-LVAD QRSd exhibited a significant association with post-LVAD cardiac structural and functional improvement (OR:0.987, 95% CI:0.977-0.998, p=0.027) and the predictive model showed a c-statistic of 0.73 with p<0.001. The correlations for baseline QRSd with pre- to post-LVAD change in LVEF and LVEDD were also investigated in ‘R’ and ‘NR’ groups. CONCLUSION Chronic advanced HF patients with a shorter baseline QRSd exhibit an increased potential for cardiac recovery after LVAD support.