Clinical radiation audits as a tool for the optimization of radiation exposure in cardiac electrophysiology procedures.

Background: Clinical radiation audits are useful to reduce ionizing radiation in clinical practice. The first Swiss radiation audit in Cardiology took place at the University Heart Center Zurich in 2019.

Objectives: To compare local diagnostic reference levels (DRLs) in cardiac electrophysiology (EP) procedures to the currently available national DRLs and to examine patient radiation exposure before and after the clinical radiation audit.

Methods: Retrospective study including 775 patients undergoing EP procedures from 2018- 2020. Main recommendations of the clinical audit were the regular use of collimation, semitransparent filters, the reduction of cine images and frame rates. Patient radiation exposure was evaluated with cumulative doses, fluoroscopy times and dose-area product (DAP). Secondary endpoints were acute procedural success rates and 30-day complications.

Results: 447 (57.5%) patients prior to, and 328 (42.3%) after the audit were included. Cryoballoon pulmonary vein isolation (PVI) was performed in 14.1%, PVI radiofrequency (RF) ablation in 26.8%, RF ablation of right-sided supraventricular tachycardia in 32.1%, other procedures in 27% of cases. Local DRLs for the DAP were below national DRLs (1 Gy cm² vs 150 Gy cm² for AVNRT/AVRT ablation). After the audit, there was a significant radiation reduction for right-sided supraventricular tachycardia ablation (cumulative dose: 4.8 mGy vs 2.1 mGy and fluoroscopy times: 210 seconds vs 107 seconds, p < 0.001) and PVI with RF (50.4 mGy vs 29.5 mGy, and 378 seconds vs 191 seconds, p < 0.003; respectively). No significant differences were found in acute procedural success rates or 30-day complications.

Conclusions: The clinical radiation audit was associated with a significant reduction of patient radiation exposure for right-sided supraventricular tachycardia ablation and PVI with RF.