Purpose: The influence of left atrial (LA) enlargement on the efficacy of steerable sheath usage during pulmonary vein (PV) isolation is poorly understood. Here, we compared the catheter-tissue contact force (CF) and clinical outcomes between steerable and non-steerable sheaths among patients with different severities of LA enlargement.
Methods: In this prospective observational study, 90 consecutive atrial fibrillation patients scheduled for PV isolation (paroxysmal, 67 %) were enrolled and divided into tertiles of the LA volume (LA1, <124 cm3; LA2, 124 to 145 cm3; LA3, ≥146 cm3). An ipsilateral PV isolation was completed using either a steerable (n = 57) or non-steerable sheath (n = 33).
Results: The average CF of each ipsilateral PV was lower in the LA3 group (right 13.8 ± 5.8 g; left 9.7 ± 5.2 g) than LA1 (right 15.6 ± 6.8 g, p = 0.005; left 12.5 ± 5.6 g, p < 0.0001) or LA2 (right 15.2 ± 7.3 g, p = 0.04; left 12.6 ± 5.3 g, p < 0.0001) groups. In total, the average CF around the left PVs was significantly higher with steerable sheaths than without (12.7 ± 5.5 vs. 10.2 ± 4.9 g, p = 0.03). Subgroup analysis revealed that a tendency toward higher CF around the left PVs was observed in the LA3 group (12.3 ± 7.3 vs. 8.5 ± 3.9 g, p = 0.08) but was not in the LA1 and LA2 groups. Further, in the LA3 group, steerable sheath usage showed better clinical outcomes: shorter procedural (55 ± 29 min vs. 81 ± 39 min, p = 0.04) and fluoroscopic times (27 ± 11 min vs. 37 ± 17 min, p = 0.045) and a tendency toward a lower 1-year AF recurrence rate (39 vs. 12 %, p = 0.09).
Conclusions: The beneficial effects of using steerable sheaths were more prominent in patients with severe LA enlargement.
Keywords: Atrial fibrillation; Contact force; Left atrial size; Pulmonary vein isolation; Steerable sheath.