ALCOHOL CONCENTRATION DETERMINES THE TYPE OF ATRIAL ARRHYTHMIA INDUCED IN A PORCINE MODEL OF ACUTE ALCOHOLIC INTOXICATION

Alcohol abuse has long been suspected clinically to cause paroxysmal a trial tachyarrhythmias. However, such a relationship has never been co nclusively proven, partly due to the lack of experimental evidence. Al though atrial fibrillation (AF) is the most common atrial arrhythmia a ttributed to acute alcoholic ingestion, atrial flutter has occasionall y been noted. We analyzed the possible role of alcohol in initiation a nd/or maintenance of a variety of atrial tachyarrhythmias in a dosed-c hest porcine model. Nine pigs underwent nine endocardial right atrial stimulation protocols (RASP) at baseline and 17 HASPs after increasing doses of ethanol (first infusion 1,230 mg/kg, second infusion 870 mg/ kg) by means of one multipolar catheter advanced under heavy sedation from the femoral vein. Each RASP included 1, 2, and 3 extrastimuli, an d rapid pacing at 5 times diastolic threshold. Venous ethanol concentr ations were measured (HPGC method) every 10 minutes and at the time of arrhythmia induction. Atrial tachyarrhythmias were induced in 4 of 9 baseline RASPs, and lasted for ct mean of 21 seconds, and in 16 of 17 RASPs after alcohol lasting for a mean of 357 seconds. Only fibrillati on was observed at the baseline RASP. The atrial tachyarrhythmias indu ced after alcohol were AF in 11 RASPs and atrial flutter in 5 RASPs (i n 5 animals). The mean venous ethanol concentration at the time of the longest arrhythmia induced for each RASP were 200 +/- 89 mg/dL for RA SP inducing fibrillation and 292 +/- 40 mg/dL for RASP inducing flutte r (P < 0.05). Flutter tended to be sustained (> 2 minute in duration) more often than fibrillation (4 of 5 flutter vs 2 of 11 fibrillation P < 0.05). In three experiments, atrial flutter persisted for > 10 minu tes and was terminated by overdrive atrial pacing. We concluded: (1) i n this closed-chest porcine model, an ethanol infusion facilitates a v ariety of atrial arrhythmias related to the ethanol concentration; (2) flutter fended to be sustained, and ifs termination by overdrive paci ng suggests the possibility of an alcohol induced reentrant mechanism; and (3) the higher concentration required for atrial flutter, exceedi ng that usually seen in humans, may help to explain the rarity of atri al flutter in clinical alcohol intoxication.