Development of a novel ablation hood to prevent systemic embolization of microbubbles and particulate emboli

Atrial fibrillation ablation results in microbubbles and particulate emboli formation. We aimed to develop and test the early feasibility of a novel ablation hood to contain microbubbles and particulate emboli with the ultimate goal of preventing systemic embolization.

In seven canines, we developed, iterated, and tested a novel retractable hood that can cover the catheter-tissue ablation site. The number and volume (nL) of microbubbles formed during ablation with and without the hood was measured using an extracorporeal circulation loop. Wilcoxon's signed-rank test was used to compare the number of bubbles detected with and without the hood.

The hood reduced systemic embolization of microbubbles in 21/28 (75%) of ablations. Both atrial and ventricular ablations showed a statistically significant reduction in bubble number (476 ± 811 without hood vs 173 ± 226 with hood, p = 0.02; 2669 ± 1623 without hood vs 1417 ± 970 with hood, p = 0.04, respectively) and bubble volume (3.3 ± 7.6 nL without hood vs 0.2 ± 0.56 nL with hood, p = 0.006; 6.1 ± 5.2 nL without hood vs 1.9 ± 1.4 nL with hood, p = 0.05, respectively).

Use of a novel hood to cover the ablation catheter at the site of catheter-tissue contact has the potential to provide a means to reduce systematic embolization of microbubbles. Further work is required to examine particulate emboli, but these data show the early feasibility of this design concept.