Impact of Cardiac Resynchronization Therapy on Exercise Performance, Functional Capacity, and Quality of Life in Systolic Heart Failure With QRS Prolongation: COMPANION Trial Sub-Study

De Marco, Teresa; Wolfel, Eugene; Feldman, Arthur M.; Lowes, Brian; Higginbotham, Michael B.; Ghali, Jalal K.; Wagoner, Lynne; Kirlin, Philip C.; Kennett, Jerry D.; Goel, Satish; Saxon, Leslie A.; Boehmer, John P.; Mann, David; Galle, Elizabeth; Ecklund, Fred; Yong, Patrick; Bristow, Michael R.

doi:10.1016/j.cardfail.2007.08.003

« Previous Next »Journal of Cardiac Failure
Volume 14, Issue 1 , Pages 9-18, February 2008

Impact of Cardiac Resynchronization Therapy on Exercise Performance, Functional Capacity, and Quality of Life in Systolic Heart Failure With QRS Prolongation: COMPANION Trial Sub-Study

Teresa De Marco, MD
- University of California, San Francisco Medical Center, San Francisco, CA
- Reprint requests: Teresa De Marco, MD, FACC, University of California, San Francisco, Division of Cardiology, 505 Parnassus Avenue, 1180-M, San Francisco, CA 94143-0124.
Eugene Wolfel, MD
- University of Colorado Health Sciences Center, Denver, CO
Arthur M. Feldman, MD, PhD
- Thomas Jefferson Medical College, Philadelphia, PA
Brian Lowes, MD
- University of Colorado Health Sciences Center, Denver, CO
Michael B. Higginbotham, MD
- Duke University, Chapel Hill, NC
Jalal K. Ghali, MD
- Wayne State University School of Medicine, Detroit, MI
Lynne Wagoner, MD
- University Hospital, Cincinnati, OH
Philip C. Kirlin, MD
- The Care Group at Methodist Hospital, Indianapolis, IN
Jerry D. Kennett, MD
- Missouri Cardiovascular Specialists, Columbia, MO
Satish Goel, MD
- Baptist Medical Center, Jacksonville, FL
Leslie A. Saxon, MD
- University of Southern California, Keck School of Medicine, Los Angeles, CA
John P. Boehmer, MD
- Milton S. Hershey Medical Center, Penn State School of Medicine, Hershey, PA
David Mann, MD
- Cardiovascular Associates, Louisville, KY
Elizabeth Galle, MS
- Boston Scientific CRM, St. Paul, MN
Fred Ecklund, MA
- Boston Scientific CRM, St. Paul, MN
Patrick Yong, MSEE
Michael R. Bristow, MD, PhD
- University of Colorado Health Sciences Center, Denver, CO
- Boston Scientific CRM, St. Paul, MN

Received 14 November 2006; received in revised form 27 July 2007; accepted 1 August 2007. published online 05 November 2007.

Abstract

Background

A total of 405 participants in the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure trial were prospectively enrolled in an exercise sub-study designed to study the influence of cardiac resynchronization therapy (CRT) on measures of exercise capacity, functional capacity, and quality of life (QOL).

Methods and Results

Substudy eligibility included New York Heart Association (NYHA) functional Class III or IV heart failure, left ventricular ejection fraction ≤0.35, QRS interval of ≥120 ms, normal sinus rhythm, a heart failure hospitalization (or equivalent) within 1 year, a peak VO₂ ≤22 mL·kg·min, the ability to walk 150 to 425 meters in 6 minutes, forced expiratory volume in 1 second/forced vital capacity ≥50%, and no clinical indication for a pacemaker or implantable cardioverter-defibrillator. Patients were randomized in a 1:4 ratio to optimal medical therapy (OPT) or to OPT plus CRT. Cardiopulmonary exercise testing (peak VO₂ and 6-minute walk distance [6MWD]) and assessment of NYHA functional class and QOL were assessed at baseline and at 3 and 6 months of assigned therapy. There was no significant improvement in peak VO₂ at 6 months in the CRT group compared with the OPT group (+0.63 mL·kg·min) by unadjusted analysis (P = .05) or by analyses adjusted for missing data. Thus the primary end point of the study was not met. There was significantly greater improvement in the 6MWD in the CRT group compared with the OPT group at both 3 and 6 months by both statistical methods (P ≤ .045). Likewise, a greater proportion of CRT patients improved by 1 or more NYHA functional classes (P < .01) at 3 months and had better QOL scores (P < .01) at 3 and 6 months compared with the OPT patients. Baseline peak VO₂ predicted clinical events (time to death, time to death or first hospitalization, or time to death and first heart failure hospitalization: P < .05) in CRT participants.

Conclusion

CRT patients with moderate to advanced symptoms of systolic heart failure and prolonged QRS intervals benefit from the addition of CRT to OPT in terms of exercise capacity, functional status, and QOL. CRT should be considered standard therapy in this select group of heart failure patients.

Key Words: Peak VO₂, 6-minute walk distance, New York Heart Association functional class