Introduction:
Pulmonary vein isolation (PVI) with radiofrequency (RF) or cryoballoon
ablation (CBA) is a common therapy for patients with drug refractory
paroxysmal atrial fibrillation
(AF).1 However, studies
have reported the success rate of ablation to be around 70-80% after
one year of
follow-up.2-4 The exact
etiology for certain patients not benefiting from this procedure remains
unclear but likely includes pulmonary vein anatomy, underlying
cardiovascular disease, valvular heart disease (VHD), older age, dilated
left atrium (LA), obesity, undiagnosed sleep apnea and the procedure
being performed at less experienced
centers.5-11 Since CBA
requires circumferential adhesion of the ablation catheter to the PV
ostium, the role of PV anatomy influencing the success of CBA has always
been
debated.12,13Isolation of a left common pulmonary vein (LCPV) can be particularly
challenging as complete circumferential occlusion with a cryoballoon
catheter is often not possible given the large size or ovality of the
ostia. Furthermore, studies evaluating the presence of an LCPV affecting
CBA outcomes have shown variable
results.5,14,15A number of single-center studies have also assessed the role of PV
anatomical indices such as eccentricity index (EI), area of vein (PVA)
and ovality index (OI) in relation to CBA
outcomes.12,13,16However, these studies were limited by a small sample size and the
inclusion of a mixed population of both paroxysmal and persistent AF
patients.
To date, the influence of PV anatomical characteristics on mid-term
outcomes in a select patient population of paroxysmal AF patients only
has never been systematically investigated. We sought to evaluate
whether the presence of an LCPV or individual PV characteristics such as
PVA, OI and EI serve as predictors of success following CBA for
paroxysmal AF patients.