B-PO03-075 A VAGAL RESPONSE DURING CRYOBALLOON ABLATION INDICATES SUCCESSFUL PULMONARY VEIN ISOLATION AND LONG TERM FREEDOM FROM SYMPTOMIC ATRIAL FIBRILLATION

Abstract

Cryoballoon ablation (CA) is an effective method of pulmonary vein isolation (PVI) as treatment for atrial fibrillation (AF). Since continuous recording of PV potentials is not always possible during CA, correlates are often relied upon to determine successful PVI. We noted that immediately upon deflation after CA, a transient drop in blood pressure (BP), implying a vagal response (VR) would at times occur. We sought to determine if a VR was a reliable marker of CA success. We evaluated if a VR which we defined as a drop in BP of >20mmHg after deflation of the balloon correlates with successful PVI in 26 patients (18 M/ 8F, 104 PV's) undergoing CA to compute the positive and negative predictive value (PPV, NPV, respectively) of a VR. Additionally, we tested if a VR relates to other factors such as gender, age, left atrial pressure (LAP), a specific vein or nadir temperature (NT) of <-50oC in 22 consecutive patients (11M/11F) with a mean age of 70 years (IQR 52-86)/88 PV's (22 LSPV/LIPV/RIPV/RSPV). 153 applications of CA were delivered to 104 PV's (78 successful, 75 unsuccessful). The PPV of a VR indicating successful PVI in all veins was 74% (LSVP 77%, LIPV 79%, RSPV 82%, RIPV 64%). The NPV of a VR not indicating PVI in all veins was 67% (LSPV 63%, LIPV 53%, RSPV 72%, RIPV 87%). Female experienced a VR more often than males (31/44 (71%) vs 21/44 (47%), p=0.03). Older age correlated with a VR (mean age with VR = 72 years vs 67 years) (p = 0.03) as well as the degree of drop in BP (r=0.187, p=0.04). NT correlated with a VR, specifically NT <-50oC correlated with VR (OR= 2.45, p=0.003) implying it too was an accurate marker for PVI success. There was no relationship of VR to superior vs inferior or left versus right PV's. There was a relationship between LAP at the beginning of the procedure (>12mmHg) and VR (OR=2.7, p=0.45). After 2 years of follow up, 82% of pts remained free of symptomatic AF. A VR during CA correlates with successful PVI with an excellent PPV and NPV. Although the degree of predictive value varied per vein, there was no difference in its value to any particular vein. VR was seen more prevalent in females, older age and elevated LAP. Pts who underwent CA demonstrating VR displayed long term prevention of AF after 2 years of follow up.