A case of prolonged sinus arrest for 5 minutes after Cryo‐balloon ablation to the left superior pulmonary vein

Abstract A 63‐year‐old man was referred to our hospital for his palpitation due to atrial fibrillation. He was admitted for catheter ablation. Cryoablation was applied to the left superior pulmonary vein for 180 seconds, and its potential disappeared in 22 seconds. The lowest temperature was −45°C. Suddenly, sinus arrest was observed 1 minute after the completion of freezing. The right ventricle was paced but no atrial potential was observed for 5 minutes until normal sinus rhythm resumed. We report a case of severe sinus arrest after cryoablation to the left pulmonary vein.


| C A S E DE SCRIP TI ON
A 63-year-old man was referred to our hospital for palpitation due to drug-resistant paroxysmal AF. He had a history of faintness twice after drinking alcohol. He was admitted to our hospital for CBA. A After a transseptal puncture, Agilis sheath (SJM) was inserted to the left atrium. SL0 sheath was exchanged over a guidewire for a 15F steerable sheath (FlexCath Advance; Medtronic) and a 20 mm circular mapping catheter (Optima; SJM) was inserted via Agilis sheath for mapping PV potentials ( Figure 1A). A spiral mapping catheter (Achieve; Medtronic) was used to advance a second-generation CB (Arctic Front Advance; Medtronic) into PV. An electrode catheter for emergency backup pacing was placed to the right ventricle from the 10 F sheath.
A 28 mm CB was inflated proximal to the PV ostium, followed by a gentle push aiming for the complete sealing at the antral aspect of the PV. Freezing was started from the LSPV, and the potential disappeared in 22 seconds after the start of ablation ( Figure 1B).  Otherwise there was no complication, and he was discharged as scheduled.

| D ISCUSS I ON
We report a case of significant sinus arrest occurred for about 5 minutes after CBA to the LSPV. It is well known that both RFA and CBA around PV ostia often induce VR. 4 The incidence of VR was reported as high as 26.8%-38.2%, and the median time of duration was 41-50 seconds and the range was 10-69.3 seconds. 3,4 Compared with such reports, the present case presented excessive activity of VR for a long time of 317 seconds before complete recovery.
As far as we know, there is no report that sinus arrest and bradycardia lasted for more than 5 minutes.
Holter monitoring and GP stimulation test were not performed.
However, SNRT and ERP are both within normal range after procedure. Although these results may not reflect natural status due to post procedure, intrinsic sinus rhythm was intact. VR was reported to be related to epicardial adipose tissue (EAT) around the PV. 3  Atropine is effective in preventing VR induced by CBA. 5 For this patient, however, administration of atropine injection in two doses was not effective. Therefore, etilefrine was administered. We should have given atropine sulfate injection once more as indicated to follow ESC guidelines, but we did not try it due to low blood pressure.
Vagal activity was too strong to be blocked by atropine injection.
Transient bradycardia is often complicated with the ablation to this vein, provoking VR. There report showed that CBA to the right PV (RPV) markedly suppressed VR of LSPV. 4 Patients with history of suspected neuroregulatory syncope may experience significant bradycardia during CBA. Therefore, we may need to avoid this response by CBA applying RPV first or by prophylactic atropine administration.

| CON CLUS ION
We report a case of severe sinus arrest after cryoablation of the left pulmonary vein.

CO N FLI C T S O F I NTE R E S T S TATE M E NT
The authors declare that there is no conflict of interest.