Cryoballoon ablation of paroxysmal atrial fibrillation within the dilated coronary sinus in a case of persistent left superior vena cava.

Trigger sources of paroxysmal atrial fibrillation (PAF) are not limited to a pulmonary vein origin and may be achievable by cardiac vascular structures like the coronary sinus (CS), the vena cava superior and in some rare cases by a persistent left superior vena cava (LSVC). Cryoballoon ablation has been shown to be effective in pulmonary vein isolation. We report an unusual case of using this technique in the dilated CS in case of a persistent LSVC. A 64 year old patient presented PAF recurrences after cryo pulmonary vein isolation 4 months before. A maintaining pulmonary vein isolation could be demonstrated by transseptal mapping. Further bi-atrial mapping localized repetitive atrial trigger activity in a dilated CS proceeding to a LSVC. A cryoballoon was deployed in the CS target area and during cryoablation the triggered activity suspended. Ablation side effects were excluded by coronary angiography. During a follow up time of 8 months the patient has remained free of PAF recurrences. The current report underlines the importance of a patient-tailored ablation approach. Cryothermic balloon technology may be more applicable in delicate cardiac structures by developing new anatomically adapted balloon shapes and sizes.