Electrophysiological mapping and histological examinations of the swine atrium with sustained (> or =24 h) atrial fibrillation: a suitable animal model for studying human atrial fibrillation.
OBJECTIVE
Interventional elimination of chronic persistent atrial fibrillation (AFib) remains difficult. An animal model mimicking the clinical situation is important.


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 (> or =24 h) in adult pigs is a feasible and efficient animal model with electrophysiological and histological characteristics closely similar to those seen in humans.
Lin
Jiunn-Lee
JL
Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan, ROC. jiunn@ha.mc.ntu.edu.tw
Lai
Ling-Ping
LP
Lin
Chih-Shen
CS
Du
Chao-Cheng
CC
Wu
Tsu-Juey
TJ
Chen
Shih-Ping
SP
Lee
Wen-Chuan
WC
Yang
Ping-Cheng
PC
Tseng
Yung-Zu
YZ
Lien
Wen-Pin
WP
Huang
Shoei K Stephen
SK
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D018780:Body Surface Potential Mapping; D002304:Cardiac Pacing, Artificial; D003452:Cryosurgery; D004195:Disease Models, Animal; D004452:Echocardiography; D022062:Electrophysiologic Techniques, Cardiac; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology; D008854:Microscopy, Electron; D008955:Models, Cardiovascular; D032383:Myocytes, Cardiac / Q000473:pathology; D010138:Pacemaker, Artificial; D011405:Propafenone / Q000627:therapeutic use; D013318:Stroke Volume / Q000502:physiology; D016019:Survival Analysis; D013552:Swine; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D011405:Propafenone