Address for correspondence Dorota Zyśko E-mail: dzysko@wp.pl Funding sources none declared Conflict of interest none declared Received on April 3, 2016 Revised on July 11, 2016 Accepted on January 1, 2017 Abstract Background. Cardiac arrhythmias are common in pregnant women. In most cases, they do not require treatment other than rest, electrolyte supplementation and avoidance of strong coffee and tea. Persistent arrhythmia or the ventricular rate running at a high frequency may cause hemodynamic deterioration in the fetus or in both the fetus and the mother. Objectives. The aim of this study was to assess the prevalence and characteristics of arrhythmias in preg- nant women who qualified for ablation as well as the feasibility and specific features of these interventions. Material and methods. The study group consisted of 11 pregnant women (16–32 Hbd) aged 31 + 6. The control group consisted of 111 women aged 15–50 years (34 + 10), scheduled for ablation in 2012. The medical records of the selected study and control groups were analyzed and the following data was retrieved: age, the reason the ablation procedure was performed, the ablation duration, the number of radiofrequency applications, the total duration of radiofrequency applications, gravity, and comorbidities. Results. In the study group, accessory pathway related arrhythmias or atrial tachycardia (AT) accounted for 62% of cases, whereas in the control group for 32% (p = 0.042). All the procedures in the study group were performed with an electroanatomical system without fluoroscopy. All of the patients, but one, had no recurrence of arrhythmia. There were no complications and no overt effects were noted in the fetus. Conclusions. Ablation of arrhythmias during pregnancy is rare. An experienced surgeon using electroana- tomical system is usually able to ablate arrhythmic substrate without the use of X-ray fluoroscopy. The most prevalent causes of arrhythmias in pregnant women requiring ablation are accessory pathway and AT focus. Key words: safety, ablation, cardiac arrhythmias DOI 10.17219/acem/68275 Copyright © 2017 by Wroclaw Medical University This is an article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc-nd/4.0/) Original papers Catheter ablation of cardiac arrhythmias in pregnancy without fluoroscopy: A case control retrospective study Edward Koźluk 1, A–F , Agnieszka Piątkowska 2, A, B, E, F , Marek Kiliszek 3, A, B, E, F , Piotr Lodziński 1, A, E, F , Sylwia Małkowska 1, A, B, E, F , Paweł Balsam 1, A, B, E, F , Dariusz Rodkiewicz 1, A, B,E, F , Radosław Piątkowski 1, A, B, E, F , Dorota Zyśko 2, A–F , Grzegorz Opolski 1, A, B, E, F 1 1 st Chair and Department of Cardiology, Medical University of Warsaw, Poland 2 Chair of Emergency Medicine, Wroclaw Medical University, Poland 3 Department of Cardiology and Internal Diseases, Military Institute of Medicine, Warszawa, Poland A – research concept and design; B – collection and/or assembly of data; C – data analysis and interpretation; D – writing the article; E – critical revision of the article; F – final approval of article Advances in Clinical and Experimental Medicine, ISSN 1899-5276 (print), ISSN 2451-2680 (online) Adv Clin Exp Med. 2017;26(1):129–134