Int J Clin Exp Med 2020;13(10):8118-8126 www.ijcem.com /ISSN:1940-5901/IJCEM0108550 Case Report RVOT ventricular tachycardia ablation in a patient with atrial septal defect: a case report Gabriel Cismaru 1 , Alexandra Zgiia 1 , Sabina Istratoaie 2 , Mihai Puiu 1 , Lucian Muresan 3 , Andrei Cismaru 4 , Gabriel Gusetu 1 , Dana Pop 1 , Dumitru Zdrenghea 1 , Radu Rosu 1 1 Fifth Department of Internal Medicine, Cardiology-Rehabilitation, “Iuliu Hatieganu” University of Medicine and Pharmacy, Cluj-Napoca, Romania; 2 Department of Pharmacology, Toxicology and Clinical Pharmacology, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400337 Cluj-Napoca, Romania; 3 Cardiology Department, “Emile Muller” Hospital, 20 Avenue du Docteur René Laennec, Mulhouse 68100, France; 4 Research Center for Functional Genomics, Biomedicine and Translational Medicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, Cluj-Napoca, Romania Received January 31, 2020; Accepted April 5, 2020; Epub October 15, 2020; Published October 30, 2020 Abstract: PVCs originating in the RVOT are the most common form of idiopathic PVCs. However, numerous medical reports have identifed RVOT changes using cardiac MRI in patients with idiopathic PVCs. Therefore cardiac MRI is an examination that has begun to be increasingly used for ablation procedures. We present the case of a patient with high number PVCs and VT, originating in a dilated portion of RVOT. A 49-year-old male patient was referred to our cardiology department for high-burden PVC. The ECG showed frequent PVCs with an LBBB morphology and precordial transition in lead V5. Holter ECG showed > 30.000 PVC/24 hours (> 37%) with repeated episodes of non- sustained and sustained VT. Cardiac MRI excluded an ARVC, but identifed a type ostium seccundum ASD with mild dilation of the RV and RVOT. Electroanatomical mapping during PVC and VT showed earliest activation at the antero- lateral RVOT region. Catheter ablation was performed using radiofrequency current applied with a 4 mm Navistar Biosense catheter resulting in the complete disappearance of PVCs and VT episodes. At the 30 day follow-up, Holter ECG showed no PVC. At the 12 month follow-up the patient remained asymptomatic, with no PVC at Holter ECG. Our case report demonstrates that RVOT VT can associate with ASD. This association may be accidental, or due to the presence of dilated RVOT. Keywords: RVOT, premature ventricular contractions, ventricular tachycardia, catheter ablation, MRI Introduction PVCs are the most common arrhythmias found in clinical practice. Those originating from the RVOT are the most common idiopathic PVCs. Catheter ablation is considered the most suit- able approach to treat PVCs located in the RVOT, with a high success rate and a low rate of complications [1]. Atrial septal defect (ASD) is one of the most fre- quent forms of congenital heart disease. Among different types of ASD, the most fre- quent is ostium seccundum. When ASD leads to right heart chamber volume overload, the structure and function of RVOT can also be affected [2]. Several studies, using cardiac MRI in patients with idiopathic RVOT-VT have shown structural and functional changes of the RVOT in up to 70% of patients [3]. Markowitz et al. showed that up to 9% of patients with idiopathic VT had RV dilatation [4]. In patients with RV dilation, Corrado et al. found that 15/23 had abnormal voltage maps during electroanatomical map- ping, and 8/23 had no abnormality during volt- age mapping. They demonstrated that areas of low voltage correlate with abnormal fndings such as: myocardial loss and fbrofatty replace- ment [5]. RVOT-VT may be associated with ASD by chance or due to structural changes of the RVOT. We present the case of a patient with atrial septal