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Cover of Cardiac Resynchronization Therapy for Congestive Heart Failure

Cardiac Resynchronization Therapy for Congestive Heart Failure

Evidence Reports/Technology Assessments, No. 106

Investigators: , MD, MSc, , MD, , MMath, , MD, MSc, , MSc, , MLIS, , MSc, , PhD, , MD, and , MD, MSc.

Rockville (MD): Agency for Healthcare Research and Quality (US); .
Report No.: 05-E001-2ISBN-10: 1-58763-169-5

Structured Abstract


Congestive heart failure (CHF) is the fastest growing cardiovascular diagnosis in North America.


The objectives were to determine the efficacy, safety, and cost-effectiveness of cardiac resynchronization therapy (CRT) in adults with symptomatic CHF.

Data Sources:

Electronic databases (the Cochrane Heart Group Trial Registry, Cochrane Library, EMBASE, International Pharmaceutical Abstracts, MEDLINE, PubMed, Web of Science, and Trial Registries) were searched, reference lists and Food and Drug Administration (FDA) reports were checked, and authors of primary studies and manufacturers of CRT devices were contacted.

Study Selection:

Randomized controlled trials (RCT) [efficacy review] and/or prospective cohort studies [safety review]. Population: patients with symptomatic CHF and reduced left ventricular ejection fraction. Intervention: active CRT with medical therapy compared to medical therapy alone or non-active/univentricular pacing. Outcomes: mortality, heart failure hospitalizations, six-minute walk test distances, functional status (New York Heart Association [NYHA] Class), quality of life, and peri/post-implantation risks.

Data Extraction:

Data were extracted using standardized methods by two independent abstractors.

Data Synthesis:

Efficacy Review: Data were analyzed using a random effects model in Stata 7.0. Calculations included: Relative risk (RR) for dichotomous data; weighted mean difference (WMD) for continuous data; log hazards ratio for time-to-event data. All results reported with 95% confidence intervals (95% CI). Safety review: Simple pooled risks and sensitivity analysis were conducted. Decision Analysis: Cost-effectiveness of CRT was estimated using a Markov model adopting a societal perspective. Future costs and effects were discounted at 3%. Monte Carlo simulation and sensitivity analyses were used to assess robustness.

Main Results:

Efficacy: In nine RCTs (3216 patients, 85% with NYHA Class III or IV symptoms and 100% with prolonged QRS duration), CRT improved peak oxygen consumption (WMD 0.65 ml/kg/min, 95% CI 0.27 to 1.04 ml/kg/min), left ventricular ejection fraction (WMD 3.35%, 95% CI 1.22% to 5.48%), six-minute walk distance (WMD 23 meters, 95% CI 9 m to 38 m), quality of life (WMD reduction of 5.5 points, 95% CI 2 to 9 points on the Minnesota Living with Heart Failure Questionnaire), and functional class (57% improved at least one NYHA class compared to 34% of controls). Heart failure hospitalizations decreased by 32% (RR 0.68, 95% CI 0.41 to 1.12), especially in patients with NYHA III/IV symptoms (RR 0.65, 95% CI 0.48 to 0.88; number needed to treat [NNT]=12). All-cause mortality was reduced by 25% (RR 0.75, 95% CI 0.60 to 0.93, NNT=27), mainly due to 40% fewer progressive heart failure deaths (RR 0.60, 95% CI 0.36 to 1.01). Kaplan Meier curves separated at 3 months, and the risk of death was reduced 41% after the first 3 months (hazard ratio 0.59, 95% CI 0.43 to 0.81). No significant differences were seen in sudden cardiac deaths or non-cardiac deaths. Safety: In 17 prospective studies (3512 patients with CRT devices), the implant success rate was 89.9% (88.8% to 90.9%) and peri-implant death risk was 0.4% (95% CI 0.2% to 0.7%). Over a median 6 months of followup, lead dislodgement occurred in 8.5% (7.4% to 9.9%), mechanical malfunctions in 6.7% (5.4% to 8.2%), arrhythmias in 1.7% (0.8% to 3.4%), and site infections in 1.4% (0.8% to 2.3%) of patients. Decision Analysis: Optimal medical therapy for CHF in NYHA Class III patients is associated with a median gain of 2.68 (interquartile range [IQR] 2.49 to 2.85) discounted quality-adjusted life years and median $34,700 (IQR $31,400 to $38,100) cost. CRT was associated with a median gain of 3.03 (IQR 2.82 to 3.27) discounted quality-adjusted life years and median $67,600 (IQR $62,000 to $73,800) cost. The incremental cost-effectiveness of CRT compared to optimal medical therapy was median $90,700 (IQR $69,500 to $124,900) per additional quality-adjusted life year; however, costs were highly sensitive to changes in several variables, particularly the incidence of complications. The cost-effectiveness acceptability curve illustrated that the probability that resynchronization is cost-effective relative to medical therapy alone is less than 59%, given a maximum willingness-to-pay for a quality-adjusted life year of $100,000.


In patients with NYHA Class III or IV CHF despite medical management, reduced ejection fractions, and prolonged QRS duration, CRT improves functional and hemodynamic markers and reduces morbidity/mortality. Given the moderate implantation success rates, biventricular pacemaker insertions should only be done by experienced providers. The cost-effectiveness of CRT remains uncertain; additional effectiveness and cost data surrounding peri-implantation complications are required to determine whether CRT is sufficient value to be widely adopted.

Prepared for: Agency for Healthcare Research and Quality, U.S. Department of Health and Human Services.1 Contract No. 290-02-0023. Prepared by: University of Alberta Evidence-based Practice Center, Edmonton, Alberta, Canada.

Suggested citation:

McAlister F, Ezekowitz J, Wiebe N, Rowe B, Spooner C, Crumley E, Hartling L, Kaul P, Nichol G, Klassen T. Cardiac Resynchronization Therapy for Congestive Heart Failure. Evidence Report/Technology Assessment No. 106. (Prepared by the University of Alberta Evidence-based Practice Center under Contract No. 290-02-0023.) AHRQ Publication No. 05-E001-2. Rockville MD: Agency for Healthcare Research and Quality. November 2004.

This report may be used, in whole or in part, as the basis for development of clinical practice guidelines and other quality enhancement tools, or a basis for reimbursement and coverage policies. AHRQ or U.S. Department of Health and Human Services endorsement of such derivative products may not be stated or implied.

AHRQ is the lead Federal agency charged with supporting research designed to improve the quality of health care, reduce its cost, address patient safety and medical errors, and broaden access to essential services. AHRQ sponsors and conducts research that provides evidence-based information on health care outcomes; quality; and cost, use, and access. The information helps health care decisionmakers—patients and clinicians, health system leaders, and policymakers—make more informed decisions and improve the quality of health care services.

The authors of this report are responsible for its content. Statements in the report should not be construed as endorsement by the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services of a particular drug, device, test, treatment, or other clinical service.


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Bookshelf ID: NBK37415


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