Regional disparities of endocardial atrial activation in paroxysmal atrial fibrillation

Abstract

Previous experimental data suggest that atrial activity is homogeneously distributed during paroxysmal atrial fibrillation (AFib). Little is known about this in human paroxysmal AFib.

Methods: Twenty-five men and two women (mean age 49 +/- 11 years; five with structural heart disease) with paroxysmal AFib for a mean 5 +/- 6.2 years despite the use of a mean of 3.6 +/- 1.7 antiarrhythmic drugs underwent atrial mapping. The right atrium was divided into four regions: posterior (intercaval), lateral, anterior, and septal. A 14-pole catheter was positioned to assess complex electrical activity defined as the duration of continuous electrical activity or electrograms with FF intervals < 100 ms for 60 seconds (expressed as percentage of time). In addition, the left atrium (divided into three regions: posterior, anterior, and septal) was explored in 12 patients with a multipolar catheter.

Results: The complex electrical activity time between all the regions explored was significantly different. In the right atrium, the septal (74% +/- 32%; P = 0.02) and the posterior (63% +/- 32%; P = 0.04) areas were significantly more disorganized than the lateral (22% +/-23%) and anterior (21% +/- 26%) regions. In the left atrium, complex electrical activity was predominant and widely distributed (posterior: 87% +/- 11%; septal: 65% +/- 27%) except in the appendage area (anterior region: 18% +/- 14%).

Conclusions: Quantitative assessment of complex electrical activity in both atria in humans shows heterogeneous temporal and spatial distribution. This may have implications for guiding catheter ablation of AFib.