Background:
The efficiency of catheter ablation in drug-refractory atrial fibrillation (AF) is compromised by high incidence of post-ablation AF recurrences requiring multiple ablation procedures (1). Post-PVAI (pulmonary vein antrum isolation) AF recurrence is mostly due to reconnection of the previously isolated PVs (2). Earlier studies have revealed that elimination of dormant PV conduction revealed by adenosine-provocation ensures better outcome as reconnection mostly happens due to presence of incompletely ablated tissue and identification and complete ablation decrease chance of recurrence (1). Adenosine is specifically chosen for induction of triggers because it is known to transiently or permanently re-establish left atrium-pulmonary vein (LA-PV) conduction after apparently successful PV isolation (3). Datino et al have demonstrated in the canines that adenosine selectively hyperpolarizes the PVs by increasing inward rectifier potassium (K+) current and restores excitability (4). As incompletely ablated tissue can potentially cause AF recurrence, the depth and extension of the lesion are crucial factors in determining the success-rate of ablation; these in turn are directly influenced by catheter type and the radio-frequency (RF) energy settings (5). In a previous study, Matiello et al have reported cooled-tip catheter at 40w setting to be more effective in preventing recurrence than that with 30w setting (5). However, none of the earlier studies have examined the rate of PV reconnection when AF ablation is done at different power settings using open-irrigated catheters after the dormant sites are revealed by adenosine-challenge.
Hypothesis:
Use of higher wattage during ablation before and after adenosine-challenge is associated with lower rate of PV reconnection.
