Electrophysiological Analysis In The Development Of Persistent Atrial Fibrillation In Goat Model

Backgroud The aim of this study was to investigate the feasibility of goat model of persistent atrial fibrillation (AF) with chronic intermittent high frequency left atrial stimulation. And to evaluate the dynamic changes of electrophysiological parameters in conscious goats.Methods Ten female goats were instrumented with epicardial electrodes patches on the left atrium (LA) and left superior pulmonary vein (LSPV). AF was induced and maintained by home-made stimulator with frequency of 50Hz, duration of 1 second and 2 seconds intermission. Before the onset of stimulation and after the stimulation lasted for 1s, 6h, 12h, 24h and every other 24h, the stimulator was disconnected. And the duration of induced AF, AF cycle length (AFCL) in LA and LSPV were recorded. Atrial effective periods (AERP) at different basic cycle length (BCL) were measured. And atrial sizes, left ventricular diameter, left ventricular ejection fraction (EF) were measured before AF inducement and after it became persistent. Results (1) Eight of the ten goats finished the study. The first induced AF episode lasted for 5.0±4.6s. But 21±6h, 2.5±1.0d, 5.0±2.2d. 6.8±3.6d and 9.3±4.6d later, AF lasted for 3-10m. 30-60m, 6-8h. 10-12h and more than 24h respectively. Persisten AF (>24h) could be induced in all the 8 goats within 6-16 days; (2) Before AF inducement, the left atrial AERP at BCL of 500, 400, 300 and 200ms were 140.3±15.2. 141.6±16.8, 146.0±18.8 and 136.3±13.0ms respectively. And 48 hours later, they were 60.3±15.7, 61.3+23.1, 61.0±16.8 and 66.7±15ms respectively (P <0.05). But AERP could not be measured later, because of the long duration of induced AF; (3) Just after onset of stimulation, the AFCL of LA and LSPV were 152±29.0ms and 146.7±24.6ms respectively (P>0.05). After the induced AF lasted for...