A Minimally Invasive Approach for Cardiac Electrophysiology Studies in Mice

Review A Minimally Invasive Approach for Cardiac Electrophysiology Studies in Mice Min Zi , * , Sabu Abraham , Alicia D'souza , David Hutchings , Sukhpal Prehar , Xin Wang , and Elizabeth J Cartwright Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, United Kingdom * Correspondence: min.zi@manchester.ac.uk Received: 6 January 2023 Accepted: 9 February 2023 Published: 25 March 2023 Abstract: Atrial fibrillation and ventricular tachycardia are commonly seen in clinic. Different approaches have been developed to investigate underlying mechanisms. Transvenous approach (TA) is widely used for studies but has several drawbacks. We therefore developed a novel minimally invasive approach (MIA) for mechanistic studies. Study included 27 male C57BL/6J mice, 19 for MIA and 8 for TA. Under general anaesthesia, ECG was recorded. A key hole was made on the right first intercostal space by separating the intercostal muscles, followed by the exposure of the superior vena cava and the top of the atrium. An EPR-800 catheter was inserted vertically, perpendicular to the chest, for atrial pacing and flatly over the ventricles for ventricular pacing. Burst S1–S1 and decremental S1–S2 pacing protocols were performed to evaluate SA recovery time (SNRT), the atrioventricular node effective refractory period (AVN-ERP), Wenckebach period, ventricular ERP, and arrhythmia susceptibility. MIA was successfully performed in all 19 mice without any complications. One mouse died during TA due to venous rupture. Compared MIA with TA, surgical time were significantly shorter (P<0.0001). Wenckebach period was shorter as well (P<0.05). No difference was found in baseline sinus cycle length, SNRT, correct SNRT, AVN-ERP, ventricular ERP, and arrhythmia susceptibility (all P>0.05). The novel MIA outplays TA by providing similar outcomes of PES but consuming less time, demanding less surgical expertise, and reducing the potential of surgical complications. Given the minimal tissue injury, it also provides great potential as a recovery procedure for longitudinal study.