Entrance Skin Dose during Radiofrequency Catheter Ablation for Tachyarrhythmia: A Multicenter Study

BACKGROUND: To assess the entrance skin dose (ESD) during radiofrequency catheter ablation procedures for tachyarrhythmia including atrial fibrillation (Af). METHODS: This study focused on 99 consecutive patients who underwent procedures for tachyarrhythmia (Af; n = 34, non-Af; n = 65) in three institutions. The non-Af group included atrial flutter, atrial tachycardia, paroxysmal supraventricular tachycardia, ventricular tachycardia, ventricular premature contraction, atrial premature contraction, atrioventricular nodal reentry tachycardia, and Wolff-Parkinson-White syndrome. In two of the three institutions, the procedures were performed for both Af and non-Af. The ESDs were measured using 100 radiosensitive indicators attached to the back of each patient's jacket at 5-cm intervals. For statistical analyses, multiple regression analysis (the dependent variable, Max-ESD; and the independent variables, dose area product [DAP], total fluoroscopic time [TFT], body mass index, etc.), Pearson's correlation test, and the Mann-Whitney test were employed. RESULTS: The overall averages for the TFTs, the DAPs, and the Max-ESDs were 49.9 ± 28.2 minutes, 71.2 ± 73.7 Gy cm(2) , and 0.57 ± 0.51 Gy, respectively. DAP was positively related to the Max-ESD and was significant in stepwise multiple regression analysis (P < 0.0001). There was a significant association between TFT and Max-ESD in five of the six kinds of angiographic unit, and between DAP and Max-ESD in all three systems with available DAP measures. In one institution, TFT, DAP, and Max-ESD differed significantly between the Af and non-Af groups (P = 0.0002, P < 0.0001, and P < 0.0001). CONCLUSIONS: During the cardiac catheter ablation, ESDs of only a few patients exceeded the thresholds of radiation skin injuries, and the DAP proved useful to estimate each patient's Max-ESD.