Author + information
- Received December 29, 2014
- Revision received January 26, 2015
- Accepted January 29, 2015
- Published online March 1, 2015.
- Saadia Sherazi, MD, MS∗∗ (, )
- Valentina Kutyifa, MD, PhD∗,
- Scott McNitt, MS∗,
- Mehmet K. Aktas, MD∗,
- Jean-Philippe Couderc, PhD∗,
- Benjamin Peterson, MD∗,
- Poul Erik Bloch Thomsen, MD†,
- Joseph Kautzner, MD, PhD‡,
- Arthur J. Moss, MD∗ and
- Wojciech Zareba, MD, PhD∗
- ∗Cardiology Division, Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, New York
- †Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark
- ‡Department of Cardiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
- ↵∗Reprint requests and correspondence:
Dr. Saadia Sherazi, Heart Research Follow-up Program, Cardiology Division, University of Rochester Medical Center, 265 Crittenden Boulevard, Box 653, Rochester, New York 14642.
Objectives This study sought to evaluate the prognostic value of heart rate variability (HRV) for death or heart failure in patients with mildly symptomatic heart failure undergoing cardiac resynchronization therapy with a defibrillator (CRT-D).
Background There are limited data regarding the prognostic value of HRV as a means of identifying high-risk patients treated with CRT-D.
Methods We analyzed the relationship between pre-implant time-domain (SD of all normal-to-normal RR intervals [SDNN], SDs of averaged 5-min normal-to-normal RR intervals, root mean square of successive differences, and mean of the SDs of all normal-to-normal RR intervals for all 5-min segments of the entire recording), and frequency-domain (low-frequency power, very-low-frequency power [VLF], high-frequency power, low-frequency power/low-frequency power ratio) HRV parameters, and the end point of death or heart failure and death alone. Study subjects include 719 patients in normal sinus rhythm enrolled in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial–Cardiac Resynchronization Therapy); outcomes of CRT-D patients with low HRV (lower tertile) were compared with CRT-D patients with preserved HRV (2 upper tertiles) and with patients receiving implantable cardioverter-defibrillators only.
Results During a mean 3.4 ± 0.9 years of follow-up, 124 patients reached the primary end point of death or heart failure, and 47 died. In multivariate analysis, low SDNN (≤93 ms) was associated with significantly higher risk of death or heart failure (hazard ratio [HR] 1.63 [95% confidence interval (CI): 1.12 to 2.36]; p = 0.010) and mortality (HR 2.10 [95% CI: 1.14 to 3.87]; p = 0.017) compared with higher SDNN (>93 ms). Similarly, low VLF (≤179 ms2) was associated with an increased risk of death or heart failure (HR 2.14 [95% CI: 1.46 to 3.13]; p < 0.001) and death alone (HR 2.49 [95% CI: 1.35 to 4.57]; p = 0.003). There was no significant difference in outcome between low HRV patients treated with CRT-D and patients receiving an implantable cardioverter-defibrillator only.
Conclusions Our findings indicate that autonomic dysfunction (quantified by low SDNN and low VLF) identified patients with no benefit or limited benefit from cardiac resynchronization therapy. Pre-implant HRV analysis might help in optimizing qualifications for this treatment.
MADIT-CRT was supported by a research grant from Boston Scientific to the University of Rochester School of Medicine and Dentistry. Dr. Kautzner is on the advisory board for Boston Scientific, Biosense Webster, Medtronic, and St. Jude Medical. All other authors have reported that they have no other relationships relevant to the contents of this paper to disclose. Drs. Sherazi and Kutyifa contributed equally to this work.
- Received December 29, 2014.
- Revision received January 26, 2015.
- Accepted January 29, 2015.
- American College of Cardiology Foundation