Efficacy of functional substrate map-guide approach for wide circumferential pulmonary vein isolation

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Pulmonary vein isolation (PVI) with anatomical approach targeting closer interlesion distance (ILD) would be effective, but not efficient. A functional substrate map (FSM) can reveal the unnecessary application site including physiological block and the critical ablation site including direct epicardial connections. PURPOSE: We investigated the efficacy of FSM-guide approach for wide circumferential PVI. METHODS: We enrolled 55 consecutive patients underwent radiofrequency PVI for atrial fibrillation. In earlier 27 patients were ablated by anatomical approach with closer ILD (<5mm) (control group), in latter 28 patients were by real time PV electrogram and high density electro-anatomical map guide (FSM-guide group). In FSM-guide group, characteristics of electrical conduction including voltage, direction , velocity and barrier between PV and left atrium and epicardial connection were assessed by local activation, coherent and ripple map before ablation. Distributions of the segments required or unnecessary ablation for PVI completion were examined. RESULTS: The success rate of first-pass isolation was higher in FSM-guide group than in control (96.4% vs. 74.1%). The number of required ablation tags for PVI were significantly lesser in FSM-guide group than control group (left-sided PV (LPV); 23.2±1.6 vs. 29.2±1.6, p=0.0112, right-sided PV (RPV); 22.6±1.7 vs. 32.4±1.8, p=0.0124, respectively). The time for PVI completion was significantly shorter in FSM-guide group than control group (RPV; 17.0±2.2 min vs. 25.2±2.8 min, p=0.0124, LPV; 18.7±1.5 min vs. 20.5±1.5 min, p=0.042, respectively). In FSM-guide group, unnecessary application sites were frequently located at posterior of RIPV (46%), anterior of LIPV (43%) and anterior of RSPV (35.7%). Frequently required segments for PVI completion were roof and carina of LPV and roof and posterior of RPV. In most cases of control group, full circumferential ablation was required (LPV 22/27(81%) and RPV 24/27(89%)). Acute reconnections during procedure were similar in FSM-guide group and control group (LPV; 6/28 (21.4%) vs. 4/27 (14.8%), p=0.7287, RPV; 9/28 (32.1%) vs. 4/27 (14.8%), p=0.2047, respectively). All of reconnection sites in FSM-guide group were ablated site. CONCLUSIONS: FSM-guide approach for extensive PVI could reveal unnecessary application sites and result in shorter procedure with comparable ablation quality.