Abstract 15331: Very Low Frequency Heart Rate Variability Identifies Clinical and Echocardiographic Non-Responders to Cardiac Resynchronization Therapy in MADIT-CRT
Introduction: The aim of this study was two-fold: (i) to assess the predictive value of heart rate variability (HRV) for heart failure (HF) or death in mildly symptomatic HF patients undergoing cardiac resynchronization therapy with defibrillator (CRT-D); and (ii)- to evaluate the predictive ability of HRV for echocardiographic response to CRT-D.
Methods: We analyzed 24 h time-domain (SDNN, SDANN, RMSSD, SDNNIX), 5 minute supine frequency-domain (LF, VLF, HF, LF/HF) HRV parameters in 716 sinus rhythm patients with mildly symptomatic HF, LVEF ≤ 30%, and prolonged QRS ≥ 130 ms enrolled in the MADIT-CRT. For each HRV parameter patients were divided into tertiles and multivariable Cox proportional hazards regression model with stepwise approach were used. The relationship of HRV and echocardiographic response to CRT-D (non-response defined as ≤ 15% reduction in left ventricular end systolic volume [LVESV] at 1 year) was evaluated using logistic regression analysis.
Results: There were 124 patients who had the primary end point during a mean 3.4 years follow-up. In Cox model including all HRV variables and clinical variables (Age≥ 65, LVEF<25 ischemic CMP, male, LBBB), patients with low VLF <176 ms2 (T1) had significantly higher risk of HF or death compared to patients with high VLF ≥ 176 ms2 [T2-3] (Adjusted hazard ratio =2.56, p <0.001). Figure shows that low VLF patients treated with CRT-D had similar risk of HF or death to patients with ICD only devices. In multivariate analysis, the presence of low VLF was associated with a 2.2-fold (p =0.008) increase in the likelihood of an echocardiographic non-response to CRT-D. In separate analysis including LBBB patients only, lower VLF continued to predict both the clinical and echocardiographic non-responders (Adjusted HR =2.00, p =0.007 and OR =2.95, p=0.006) respectively.
Conclusion: Our findings suggest that lower VLF is an independent predictor of HF or death and identifies patients more likely to be non-responders to CRT.
- © 2013 by American Heart Association, Inc.