Electrophysiological Mapping and Histological Examinations of the Swine Atrium with Sustained (≥24 h) Atrial Fibrillation: A Suitable Animal Model for Studying Human Atrial Fibrillation

• Published in: Cardiology Vol. 99; no. 2; pp. 78 - 84
• Main Authors: Lin, Jiunn-Lee, Lai, Ling-Ping, Lin, Chih-Shen, Du, Chao-Cheng, Wu, Tsu-Juey, Chen, Shih-Ping, Lee, Wen-Chuan, Yang, Ping-Cheng, Tseng, Yung-Zu, Lien, Wen-Pin, Huang, Shoei K. Stephen
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland Karger 01.01.2003; S. Karger AG
• Subjects: Animals; Anti-Arrhythmia Agents - therapeutic use; Arrhythmias, Electrophysiology and Electrocardiography; Atrial Fibrillation - mortality; Atrial Fibrillation - pathology; Atrial Fibrillation - therapy; Biological and medical sciences; Body Surface Potential Mapping; Cardiac dysrhythmias; Cardiac Pacing, Artificial; Cardiology. Vascular system; Cryosurgery; Disease Models, Animal; Echocardiography; Electrophysiologic Techniques, Cardiac; Heart; Heart Atria - diagnostic imaging; Heart Atria - pathology; Heart Atria - surgery; Heart Ventricles - diagnostic imaging; Heart Ventricles - drug effects; Heart Ventricles - pathology; Medical sciences; Microscopy, Electron; Models, Cardiovascular; Myocytes, Cardiac - pathology; Pacemaker, Artificial; Propafenone - therapeutic use; Stroke Volume - physiology; Survival Analysis; Swine; Treatment Outcome; Animal model; Atrial compartmentalization; Antiarrhythmic drugs; Electrophysiological mapping; Atrial fibrillation; Arrhythmia; Electrophysiology; Cardiovascular disease; Histology; Left atrium; Excitability disorder; Pig; Vertebrata; Mammalia; Heart mapping; Heart disease; Animal; Artiodactyla; Right atrium; Ungulata
• ISSN: 0008-6312; 1421-9751
• DOI: 10.1159/000069728

Objectives: Interventional elimination of chronic persistent atrial fibrillation (AFib) remains difficult. An animal model mimicking the clinical situation is important. Methods and Results: Twenty-five adult pigs were implanted with a high-speed atrial pacemaker. After continuous pacing at 600 bpm for 6 weeks, 20 (91%) of the 22 survivals developed sustained AFib lasting for at least 24 h. Epicardial dense mapping revealed multiple coexisting reentrant wavelets in the left and the right atrium (LA and RA, respectively; 10.6 ± 2.9 vs. 7.6 ± 2.4 wavelets/cm 2 /s; p < 0.002). The mean local A-A intervals were 87.2 ± 14.6 ms in the LA and 103.3 ± 19.0 ms in the RA (p < 0.0002). Acute termination of sustained AFib was successful in 3 of the 5 pigs by propafenone, but in none of the 6 by dl-sotalol. Epicardial cryothermal ablation failed to terminate any AFib by compartmentalization of the RA free wall alone (4 pigs) or together with the LA appendage (4 pigs). Electron microscopic examination demonstrated diffuse perinuclear myolysis, myofibrillar fragmentation and mitochondrial crystal disruption in the atrium. Conclusions: Pacing-induced sustained AFib (≧24 h) in adult pigs is a feasible and efficient animal model with electrophysiological and histological characteristics closely similar to those seen in humans.