INTRODUCTION
Atrial fibrillation (AF) is associated with all-cause death (especially
cardiovascular death), stroke, hospitalizations, low quality of life,
left ventricular dysfunction and heart failure, and cognitive
decline/vascular dementia 1; hence, the management of
AF is important, and catheter ablation is an effective treatment. In
1998, Haissaguerre found that 94% of the ectopic beats that led to AF
were in the pulmonary vein (PV) 2, and pulmonary vein
isolation (PVI) has become an established treatment for AF. However,
several recent studies have revealed approximately 10–20% of AF
originate from non-PV foci 3-6, and the frequency of a
superior vena cava (SVC) origin is the highest 4. This
is a major cause of reoperation. Furthermore, catheter ablation is an
invasive procedure; therefore, the elimination of AF in a single
procedure is desirable. However, SVC isolation is associated with 2.1%
risk of phrenic nerve injury 7 and 4.5% risk of sinus
node injury 8 hence, performing SVC isolation
routinely in patients with AF is not recommended.
A previous seminal study reported that the effective refractory period
(ERP) in patients with AF was shorter than that in patients without AF
(185±71 vs. 282±45 ms, P <0.001) 9.
This study also suggested that shorter ERPs played a major role in the
development of AF. Another seminal study reported that a large
dispersion of the ERP within the PVs and at the PV-left atrium (LA)
junction may form a reentrant substrate and play an important role in
the maintenance of AF 10.
Although the frequency of an SVC origin was the highest among non-PV
foci for AF, the characteristics of the ERP in the SVC (SVC-ERP) were
unclear. The purpose of this study was to elucidate the relationship
between the SVC-ERP and the inducibility of AF after PVI.