Atrial Ischemia Promotes Atrial Fibrillation in Dogs

Abstract

Background-Coronary artery disease is a significant risk factor for atrial fibrillation (AF), but the basis for this association is incompletely understood. The present study evaluated the hypothesis that atrial ischemia can create a substrate for AF maintenance. Methods and Results-Atrial ischemia was induced by occlusion of an atrial arterial branch that did not provide blood flow to the ventricles. Atrial-arterial occlusion increased the duration of AF induced by burst pacing from 57Ϯ32 seconds (control) to 803Ϯ214 seconds (PϽ0.001) after 0.5 hour of occlusion and to 887Ϯ209 seconds (PϽ0.001) after 3 hours of occlusion. Prolonged AF (Ͼ20 minutes) was induced in 0 of 16 dogs (0%) under control conditions, 7 of 16 (44%, PϽ0.01) at 0.5 to 3 hours, and 5 of 13 (38%, PϽ0.01) 3 to 5 hours after occlusion. Atrial conduction was slowed substantially within the ischemic zone: eg, conduction delay was 8Ϯ1 ms at a cycle length of 200 ms, control, versus 22Ϯ5 ms (PϽ0.01) after 0.5 hours and 27Ϯ5 ms (PϽ0.001) after 3 hours of ischemia. Refractoriness was initially unaffected but was prolonged 5 hours after occlusion. Phase-delay analysis and high-density mapping confirmed severe conduction slowing in the ischemic zone. Histological examination confirmed the location of ischemic regions and revealed extensive ischemia-induced necrosis at sites of conduction delay. Conclusions-Experimental atrial ischemia creates a substrate for AF maintenance, apparently by causing local conduction slowing that promotes reentry. These results suggest that atrial ischemia may significantly promote AF, and may be relevant to AF mechanisms in association with coronary artery disease.

Atrial Tachyarrhythmias After the Maze Procedure

“…Sinno et al have demonstrated that atrial ischemia causes slow conduction in the ischemic zone, resulting in a substrate for AF maintenance. 21 Incomplete cryoablation near the valvular annulus or coronary sinus during the Maze procedure has been postulated to incisional macroreentry around the mitral or tricuspid valves. Shah et al described slow conduction through the isthmus created by incomplete ablation causing sustained stable AFL.…”

High concentrations of omega-3 fatty acids are associated with the development of atrial fibrillation in the Japanese population

“…Atrial ischemia induced by occlusion of the atrial artery has been shown to cause local conduction slowing, with re-entry contributing to increased AF [21]. The cardiovascular effects of myocardial ischemia in ventricular infarction and dysfunction, increased atrial stretch, pericarditis, and neurohormonal and autonomic nervous system changes are potentially important contributors to a heterogeneous electrical and structural milieu, thereby increasing the risk of AF [22][23][24][25][26][27].…”

New-Onset Atrial Fibrillation in Settings of Acute Coronary Syndrome. Current Issues

“…экспериментальная ишемия миокарда предсердий приводила к нарушению про-ведения и формирования импульса, возникновению волн re-entry и развитию ФП [46]. Alasady и соавт.…”