Shunt and pace: a novel experimental model of atrial fibrillation with a volume-loaded left atrium

• Published in: General thoracic and cardiovascular surgery 2023-05, Vol.71 (5), p.272-279
• Main Authors: Ohmori, Hiroya, Sakamoto, Shun-ichiro, Miyagi, Yasuo, Ishii, Yosuke, Nitta, Takashi
• Format: Article
• Language: English
• Subjects: Animals; Anticoagulants; Atrial Fibrillation - etiology; Atrial Fibrillation - surgery; Atrial Remodeling; Cardiac arrhythmia; Cardiac Pacing, Artificial; Cardiac Surgery; Cardiology; Dogs; Electrocardiography; Electrodes; Heart Atria; Heart failure; Humans; Laboratory animals; Medicine; Medicine & Public Health; Mitral Valve Insufficiency - etiology; Mitral Valve Insufficiency - surgery; Original Article; Ostomy; Pulmonary arteries; Silicones; Sodium; Surgical Oncology; Thoracic Surgery; Veins & arteries
• ISSN: 1863-6705; 1863-6713
• DOI: 10.1007/s11748-022-01866-8

Background Atrial fibrillation (AF) is frequently seen in patients with a volume-loaded left atrium (LA) such as mitral valve regurgitation (MR). Previous animal models have incomplete relevance to human AF associated with MR. Methods A novel experimental model with a combination of volume loading of LA by creating a shunt from the subclavian artery to pulmonary artery and electrical remodeling induced by continuous rapid LA pacing was designed and the electrophysiological effects were examined in 10 canines. Five weeks after the shunt surgery, the entire atrial epicardium was mapped during sustained AF with form-fitted electrode patches with 246 bipolar electrodes and a three-dimensional dynamic mapping system to characterize the induced AF. Results Three animals died of severe heart failure and pacing failure occurred in one. Remaining six animals were subjected to the analysis. The LA diameter increased progressively after the shunt surgery. Sustained AF was induced after 3 weeks of continuous rapid LA pacing in all animals. The activation maps revealed repetitive focal activations arising from the pulmonary veins, right or left atrial regions, and reentrant activations in the RA, which patterns of atrial activations are the same as those seen in human AF. Conclusion The animal model with a combination of LA volume load and electrical remodeling was relevant to human AF associated with LA volume load. Studies using the present model may provide further knowledges of AF and may be useful in examining the effects of pharmacological and non-pharmacological therapies.