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Cardiac Resynchronization Therapy

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Full Title: Cardiac Resynchronization Therapy for Congestive Heart Failure

November 2004

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Structured Abstract

Objectives: To determine the efficacy, safety, and cost-effectiveness of cardiac resynchronization therapy (CRT) in adults with symptomatic congestive heart failure (CHF).

Review Methods: Cochrane Heart Group Trial Registry, Cochrane Library, EMBASE, International Pharmaceutical Abstracts, PubMed®, and Trial Registries. Reference lists and Food and Drug Administration (FDA) reports. Randomized controlled trials (RCT) and/or prospective cohort studies.

  • 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 were analyzed using a random effects model in Stata 7.0. Simple pooled risks and sensitivity analysis were conducted. Cost-effectiveness of CRT was estimated using a Markov model adopting a societal perspective.


  • 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, left ventricular ejection fraction, six-minute walk distance, quality of life, and functional class. Heart failure hospitalizations decreased by 32%, especially in patients with NYHA III/IV symptoms. All-cause mortality was reduced by 25%, mainly due to 40% fewer progressive heart failure deaths. Kaplan Meier curves separated at 3 months, and the risk of death was reduced 41% after the first 3 months. 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% and peri-implant death risk was 0.4%. Over a median 6 months of followup, lead dislodgement occurred in 8.5%, mechanical malfunctions in 6.7%, arrhythmias in 1.7%, and site infections in 1.4% of patients.
  • Decision Analysis: Optimal medical therapy for CHF in NYHA Class III patients is associated with a median gain of 2.68 discounted quality-adjusted life years and median $34,700 cost. CRT was associated with a median gain of 3.03 discounted quality adjusted life years and median $67,600 cost. The incremental cost-effectiveness of CRT compared to optimal medical therapy was a median $90,700 per additional quality-adjusted life year; however, costs were highly sensitive to changes in several variables.

Conclusions: 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.

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Cardiac Resynchronization Therapy for Congestive Heart Failure

Evidence-based Practice Center: University of Alberta
Topic Nominator: American Association of Health Plans

Current as of November 2004


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