Background

Pulmonary vein isolation (PVI) using a circumferential mapping catheter (CMC) is an established therapy of atrial fibrillation (AF). Novel catheters with close interelectrode spacing and high local resolution provide new insights into underlying substrate and mechanisms.

Objective

The Advisor HD-Grid^® (Abbott, St. Paul, MN, USA) is a bidirectional multipolar mapping catheter with 16 electrodes on 4 splines arranged in a grid shape. We sought to assess ultra-high-density mapping with the HD-Grid (HDG) in clinical routine AF ablation in comparison to the standard CMC approach.  

Methods

In index and repeat ablation procedures of AF and consecutives arrhythmias a standard CMC or HDG was applied. Procedural data and outcome were assessed. 

Results

A total of 200 consecutive pts (65±12 years, 62% male) were included. 100 pts respectively applying CMC and HDG. Baseline parameters did not differ between groups. In index procedures pts predominantly underwent PVI only (82% vs. 88%; p=0.2). In HDG studies significantly more map points were acquired (9962 [19691- 1300] vs. 1573±1481; p=<0.001) while mapping duration was comparable (22.4±7.5 vs. 23.7±6.8 min; p=0.6). Procedure duration (143±64 min. vs. 146±51min; p=0.3), fluoroscopy time (15.5±8.8 min. vs. 14.2±9.9 min.; p=0.2) and fluoroscopy dose (35944.4±2671.3 mGycm² vs. 3632.9±2785.3 mGycm²; p=0.1) did not differ either. Likewise, in repeat ablations HDG procedures only differed in a significantly higher map density (7555±4133 vs. 1932±1636; p=<0.001). Mapping time (24.5±8.8 vs. 26.3±6.3; p=0.4), procedure duration (163±76 min. vs. 140±70 min.; p=0.09), fluoroscopy time (20.1±13.5 min. vs. 15.9±10.1 min.; p=0.2) and fluoroscopy dose (4979.4±4656.1 mGycm² vs. 3372.5±2551.8 mGycm²; p=0.1) were comparable. Isolation of all pulmonary veins with the endpoint of non-excitability was achieved in both groups. Outcome at 6 months was nearly identical: After index procedure 71% in HDG vs. 69% of pts in CMC group (p=0.7) and after repeat procedure 79% in HDG vs. 76% in CMC group (p=0.4) were free from AF.

Conclusion

The Advisor HD-Grid^® is an efficient mapping tool in AF ablation. We showed for the first time that it can be used for PVI as safely and effectively as the standard CMC. At comparable mapping duration and fluoroscopy application the HD-Grid provides higher resolution maps, more detailed information about underlying substrate and is therefore not only an effective tool for PVI but especially for complex cases.