1. Introduction
Radiofrequency catheter ablation (RFCA) for symptomatic atrial fibrillation (AF) is an established treatment which is associated with significantly improved quality of life.1 Recent clinical trials also suggest that RFCA can improve not only quality of life but also hard clinical outcomes including all cause death in patients with both AF and heart failure.2, 3 Claim data based retrospective data also suggest that RFCA is associated with reduced risk of ischemic stroke.4, 5 Despite various benefits of RFCA in AF patients, RFCA is associated with several catastrophic complications such as procedure-related stroke or atrio-esophageal fistula.6
Time interval between occurrence of procedure-related stroke and correct diagnosis due to patient sedation delays appropriate therapy and significant proportion of patients with procedure-related stroke have permanent neurologic consequences. Optimal treatment modalities for procedure-related stroke are also not established since majority of these strokes are due to char formation during radiofrequency energy delivery.7, 8 Char formation during radiofrequency energy delivery is thought to be related with tissue overheating and acute cellular damage.9Irrigation catheters were developed in order to reduce tissue overheating and char formation.10-12 Among irrigation catheters, open-irrigation catheters showed lower interface temperature, thrombus, and steam pop compared with closed-loop irrigation catheters indicating greater interface cooling capability.13Open-irrigation catheters are further classified according to their shape: 6-holes, 12-holes, 56-holes, and slit-based irrigation system. Slit-based irrigation catheters have the largest irrigation space compared to other open-irrigation catheters. However, whether slit-based irrigation catheters are superior to other open-irrigation catheters in terms of stroke prevention remains largely unknown. We aimed to compare the risk of procedure-related ischemic complication among non-irrigation, non-slit-based irrigation, and slit-based irrigation catheters.