PV Reconnection After PVAI at Different Power Settings and Adenosine Provocation

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.

Inclusion Criteria:

1. Age ≥ 18 years

2. Patients presenting with drug-refractory PAF undergoing first ablation

3. Ability to understand and provide signed informed consent

Exclusion Criteria:

1. Previous catheter ablation or MAZE procedure in left atrium

2. Reversible causes of atrial arrhythmia such as hyperthyroidism, sarcoidosis, pulmonary
embolism etc