Spironolactone Prevents Aldosterone Induced Increased Duration of Atrial Fibrillation in Rat

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice. The ReninAngiotensin-Aldosterone-System plays a major role for the atrial structural and electrical remodelling. Recently elevated aldosterone levels have been suggested to increase the risk for the development of AF. Methods: Rats were treated with aldosterone by means of an osmotic minipump (0.5µg/h) over a period of 4 weeks. AF was induced by transesophageal burst pacing. Action potentials (AP) were recorded from left atrial preparations with microelectrodes. Atrial collagen was quantified by histological studies. Results: Aldosterone treatment resulted in hypertrophy as indicated by an increased ratio of heart weight/tibia length and doubled the time until the AF converted spontaneously into sinus rhythm (85.8±13.4 s vs.38.3±6.9 s, p