Association between ventricular pacing and persistent atrial fibrillation in patients indicated to elective pacemaker replacement: Results of the Prefer for Elective Replacement MVP (PreFER MVP) randomized study

BACKGROUND: Pacing in the right ventricle can cause a variety of detrimental effects, including atrial tachyarrhythmias (AT/AF).OBJECTIVE: To evaluate incidence and predictors of persistent AT/AF in patients with long term exposure to ventricular pacing.METHODS: In a multi-center international trial, 605 patients (75±11 years, 240 females), referred for replacement of an implanted pacemaker or cardioverter defibrillator (ICD), with history of high percentage (>40%) ventricular pacing, were randomly allocated to standard dual-chamber pacing or Managed Ventricular Pacing (MVP), a pacing modality which minimizes ventricular pacing. Main end point of this secondary analysis of the PreFER MVP randomized study was persistent AT/AF, defined as ≥7 consecutive days with AT/AF or AT/AF interrupted by atrial cardioversion or AT/AF present during 2 consecutive follow-up visits.RESULTS: Persistent AT/AF was observed in 71 patients (11.7%) after 2 years of follow-up. At multivariable Cox regression analysis, prior AT/AF (hazard ratio (HR)=2.85, 95% confidence intervals (CI)=1.20-6.22, p=0.017) and ventricular pacing percentage, estimated in the first 3 months, ≥10% (HR=3.24, CI=1.13-9.31, p=0.029) resulted as independent predictors for persistent AT/AF. MVP was associated with persistent AT/AF risk (HR=3.41, CI=1.10-10.6, p=0.024) in the subgroup of patients with a baseline long PR interval (PR>230 ms), but not in the whole population.CONCLUSION: In pacemaker and ICD replacement patients, high percentage of ventricular pacing is associated with higher risk of persistent AT/AF. The use of algorithms which minimize right ventricular pacing may benefit patients with normal spontaneous AV conduction but should be evaluated with caution in patients with long PR interval.CLINICAL TRIAL REGISTRATION: URL http://www.clinicaltrials.gov. Identifier: NCT00293241.