Discussion
Anatomically, the myocardial sleeves extended from the RA into the SVC.
Simultaneous isolation of both the RSPV and SVC implied that the
anterior aspect of the SVC had poor myocardial sleeves in the present
case. The posterior aspect of the SVC was close to the anterior aspect
of RSPV. The anatomical distance between the RSPV ostium and SVC was
significantly correlated with the conduction delay of the SVC potentials
produced during the RSPV isolation with the cryoballoon ablation. A
distance between the RSPV ostium and SVC of < 4 mm has been
demonstrated to have a significant effect on the RA-SVC junction during
cryoballoon application.6 The distance between the
RSPV ostium and SVC was just 1 mm in the patient presented here. Despite
the relatively mild cryoballoon application (150 s and nadir -44°C), the
SVC isolation had persisted for over a year. A small anatomical distance
between the RSPV ostium and SVC may be the main factor for persistent
SVC isolation following cryoballoon application.