Atrio-ventricular node ablation has been used to treat symptomatic atrial fibrillation with poor rate control although these studies have contained few subjects with low ejection fractions. Biventricular pacing has recently been shown to be superior to right ventricular pacing following atrio-ventricular node ablation.
The Pulmonary Vein Antrum Isolation (PVI) versus AV Node Ablation with Biventricular Pacing for Treatment of Atrial Fibrillation in Patients with Congestive Heart Failure (PABA-CHF) trial aimed to compare pulmonary vein isolation with atrioventricular node ablation and biventricular pacing in patients with an ejection fraction <40%, symptomatic atrial fibrillation and NYHA Class II-III heart failure. This was a prospective multicentre randomised controlled trial. The primary end-point was a composite of ejection fraction, distance on a 6 minute walk test and Minnesota Living with Heart Failure Questionnaire (MLWHF) score. Follow up was performed with a loop event monitor that patients wore from months 2-6 post-procedure. Patients recorded any symptoms and recorded at least 2-3 transmissions/week, even if they were asymptomatic.
41 patients underwent PVI and 40 AV node ablation with biventricular pacing. The composite primary end point favoured patients undergoing PVI with an improved questionnaire score at 6 months (p<0.001), a longer 6 minute walk test (340m vs 297m, p<0.001) and a higher ejection fraction (35% vs 28%, p<0.001). 88% of patients receiving anti-arrhythmic drugs in the PVI group, and 71% not receiving these agents, were free of atrial fibrillation at 6 months. In the PVI population, 2 patients developed pulmonary stenosis, 1 a pericardial effusion and 1 pulmonary oedema. In the AV node ablation and biventricular pacing arm, lead displacement occurred in 1 patient and 1 had a pneumothorax.
The AFFIRM (Atrial Fibrillation Follow-Up Investigation of Rhythm Management) Trial was a landmark study that has been argued to show a benefit of rate control over a rhythm control strategy. However subsequent analysis of the data demonstrated that rhythm control with restoration of sinus rhythm conferred survival benefit. PVI ( arguably a form of rhythm control) in this trial had a good success rate and resulted in superior morphological and functional outcomes when compared to the optimal rate control strategy (AV node ablation and biventricular pacing). 100% of patients in the AV node ablation and pacing arm had atrial fibrillation at 3 and 6 months – an unexpected finding.
Although this study is limited by the short follow-up data and the fact that the procedures were all performed in very experienced centres, it nonetheless provides strong support for PVI in centres with the appropriate experience.
- Khan MN, Jais P, Cummings J et al. Pulmonary-Vein Isolation for Atrial Fibrillation in Patients with Heart Failure. N Engl J Med 2008;359:1778-85