Authors
Linde C, Abraham WT, Gold MR, et al.
Title
Randomized Trial of Cardiac Resynchronization in Mildly Symptomatic Heart Failure Patients and in Asymptomatic Patients with Left Ventricular Dysfunction and Previous Heart Failure Symptoms
References
J Am Coll Cardiol 2008; 52: 1834-43
Background
Previous literature has shown that CRT with or without ICD improves quality of life, functional status, exercise capacity, morbidity, and mortality in patients with NYHA III/IVa heart failure with LV systolic dysfunction and a prolonged QRS duration. CRT also improves LV structure and function in this patient population.
Purpose
To determine the effects of CRT on patients with asymptomatic and mildly symptomatic heart failure and a prolonged QRS interval.
Design
Randomized, double-blind trial 610 patients with NYHA I/II heart failure for at least 3 months, sinus rhythm with QRS duration ≥ 120 ms, LVEF ≤ 40%, and LV end-diastolic diameter ≥ 55 mm. All patients on optimal medical therapy including stable doses of an ACE inhibitor or ARB and beta-blocker for at least 3 months
Exclusion Criteria
NYHA III/IV or hospitalized for HF in the 3 months before enrollment Need for cardiac pacing or paced from previous device Permanent or persistent atrial arrhythmias
Follow-Up
12 months
Treatment Regimen
Implantation of a CRT system (with or without ICD capabilities) Randomized in 2:1 fashion to CRT-ON (CRT group) or CRT-OFF (control group) Evaluation at baseline, 1 month, 3 months, 6 months, and 12 months after randomization
Results
Primary End Points: HF clinical composite response: CRT group (84% improved/unchanged, 16% worsened) vs control group (79% improved/unchanged, 21% worsened) (p = 0.10) Secondary End Points: Change in left ventricular end-systolic volume index: CRT group (- 18.4 mL/m2) vs control group (- 1.3 mL/m2) (p <0.0001) Change in QRS duration: CRT group (- 13 ms) vs control group (+ 0.2 ms) (p = 0.0007) Change in 6-minute walk distance: CRT group (+ 12.7 m) vs control group (+ 18.7 m) (p = 0.52) Change in Quality of Life Questionnaire (Minnesota questionnaire – higher score, worse QOL): CRT group (- 8.4) vs control group (- 6.7) (p = 0.26) Occurrence of VT/VF: CRT group (0.57 episodes per year) vs control group (0.70 episodes per year) (p = 0.09) HF hospitalizations: CRT group (4.1%) vs control group (7.9%) All-cause mortality: CRT group (2.2%) vs control group (1.6%) (p = 0.63)
Summary
CRT reduces the risk for heart failure hospitalization and improves ventricular structure and function in a patient population with NYHA I/II functional class, LVEF ≤ 40%, and QRS ≥ 120 ms.