LAUSR

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Electrical cardioversion (DCCV) is a long-used and proven method for the acute termination of atrial fibrillation episodes. The methodology for optimal performance of DCCV with the highest level of effectiveness while maintaining maximum safety is still under investigation. To validate our proposed methodology for performing DCCV, we have initiated the PROTOCOLENERGY clinical trial, which is currently ongoing. Objective To test the effect of conducting a clinical trial on the effectiveness of cardioversion in patients who were not included in the study for any reason. Methodology A retrospective analysis of the DCCV registry from the indications of persistent atrial fibrillation (long-term persistent excluded) from 2015-8/2022. Statistical comparison of the demographics and overall effectiveness of the DCCV cohort before and after study initiation and comparison of the cohort, enrolled and not enrolled since study initiation (no interim analysis of the study cohort proper). Heart rate 1 min after the last discharge is assessed. Cohort A total of 2402 procedures were analyzed in 829 women (34.5%) and 1573 men (65.5%) aged 67 (+/-10) years, with CHADSVASC score of 3,0 (+/− 1), BMI 31.2 (+/-7.7). Results DCCV efficiency in the whole cohort was 91.1%. Before the study, SR was achieved in 90% of the 1981 patients; since the start of the clinical trial, DCCV efficacy increased to 96.4% (in a cohort of 421 patients) (p <0.001). There was no statistically significant effect in efficacy between patients included in the clinical trial (312 pt.) and those not included (109 pt.) (96.5% vs. 96.3% p=0.944). Conclusion The presented data suggest an effect of developing and controlling the methodology of DCCV performance in a clinical trial on increasing the efficacy of DCCV, even in the cohort of patients not enrolled in the clinical trial. That phenomenon is called the HAWTHORNE effect and is related to the improvement of the outcome of the investigated phenomenon due to the influence of the actual investigation. In this case, probably due to strict adherence to the study protocol ( paddle pressure during DCCV, cardioversion in expiration, adherence to predetermined cardioversion energies, etc. even in patients not included in the study).