Effect of pulmonary vein isolation on the distribution of complex fractionated electrograms in humans

Abstract

Targeting of complex fractionated electrograms (CFEs) has been used as an adjunctive strategy to pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF). However, it is unclear whether CFEs should be targeted before or after PVI. The purpose of this study was to examine the effect of PVI on CFE distribution in humans. We compared left atrial (LA) CFE maps acquired using the NavX system before and after PVI in patients with persistent AF. CFE maps were constructed from bipolar electrograms acquired from a circular mapping catheter. At each point, the mean AF cycle length (CL) was calculated automatically by averaging the intervals between deflections over a 4-second window. Sites with mean CL < or =120 ms were considered CFE+. A total of 22 consecutive patients (82% male, age 58 +/- 9 years) were studied. At baseline, 47% of the LA was encompassed by electrograms with CL <120 ms. PVI had a significant effect on CFE characteristics, with an increase in mean LA AF CL (144 ms pre-PVI vs. 214 ms post-PVI; P <.01) and a decrease in CFE+ LA surface area (47% vs 23%; P <.01). There was significant reduction in CFE burden after PVI in both PV (50% vs. 6%; P <.01) and non-PV (61% vs. 39%; P <.01) regions. In patients with persistent AF, PVI results in a significant decrease in both PV and non-PV areas of CFE. To limit extensive LA ablation, PVI should be performed before targeting CFE when a combined approach is pursued.