Authors
Cazeau S, Leclercq C, Lavergne T, et al.
Title
Effects of Multisite Biventricular Pacing in Patients with Heart Failure and Intraventricular Conduction Delay
References
New Engl J Med 2001; 344: 873-80
Background
There is a high prevalence of intraventricular conduction delay in patients with heart failure, with resultant enhancement of the negative hemodynamic consequences of chronic LV dysfunction. Previous literature has demonstrated improvements in hemodynamic parameters, symptoms, exercise tolerance, and well-being with biventricular pacing.
Purpose
To determine the clinical efficacy and safety of biventricular pacing in patients with severe heart failure and major intraventricular conduction delay.
Design
Single-blind, randomized, controlled crossover study 67 patients with severe heart failure (non-ischemic or ischemic), LVEF < 35%, LV end-diastolic diameter > 60 mm Sinus rhythm with QRS > 150 ms, without a standard indication for pacemaker insertion NYHA III for at least one month while receiving optimal medical therapy (including diuretics and ACE inhibitors)
Exclusion Criteria
Hypertrophic or restrictive cardiomyopathy Suspected acute myocarditis Correctable valvulopathy ACS lasting < 3 months Recent coronary revascularization (< 3 months) or scheduled revascularization Treatment-resistant hypertension Severe obstructive lung disease Inability to walk Reduced life expectancy not associated with cardiovascular disease (< 1 year) Indication for implantation of ICD
Follow-Up
6 months
Treatment Regimen
Implantation of atrial lead, LV lead, RV lead, and biventricular pacemaker after one-month observation period to verify stability of heart failure (no change in treatment or functional class) Six-month randomized crossover phase comparing atriobiventricular (active) pacing with ventricular inhibited (inactive) pacing at a basic rate of 40 bpm, each for a period of three months in random order Evaluation occurred at the time of randomization and end of each of two periods of cross phase
Results
Primary End Points: Distance walked in six minutes: Active BiV pacing (399 ± 100 m) vs Inactive BiV pacing (326 ± 134 m) (p < 0.001) Secondary End Points: Quality of Life (Minnesota questionnaire – higher score, worse QOL): Active BiV pacing (29.6 ± 21.3) vs Inactive BiV pacing (43.2 ± 22.8) (p <0.001) Peak oxygen Uptake: Active BiV pacing (16.2 ± 4.7 ml/kg/min) vs Inactive BiV pacing (15 ± 4.9 ml/kg/min) (p = 0.029) Hospital Admissions for decompensated heart failure: Active BiV pacing (3) vs Inactive BiV pacing (9) (p < 0.05) Patient’s preference with regard to pacing (active vs inactive) at the end of the study: Active BiV pacing (85%) vs Inactive BiV pacing (4%) vs no preference (10%) (p < 0.001)
Summary
Biventricular pacing improves exercise tolerance and quality of life in patients with chronic heart failure (LVEF <35% and NYHA III) and intraventricular conduction delay (QRS > 150 ms).