Alcohol concentration determines the type of atrial arrhythmia induced in a porcine model of acute alcoholic intoxication.

Abstract

Alcohol abuse has long been suspected clinically to cause paroxysmal atrial tachyarrhythmias. However, such a relationship has never been conclusively proven, partly due to the lack of experimental evidence. Although atrial fibrillation (AF) si the most com- mon atrial arrhythmia attributed to acute alcoholic ingestion, atrial flutter has occasionally been noted. We analyzed the possible role of alcohol in initiation and/or maintenance of a variety of atrial tachy- arrhythmias in a closed-chest porcine model. Nine pigs underwent nine endocardial right atrial stimula- tion protocols (RASP) at baseline and 17 RASPs 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 3extrastimuli, and rapid pacing at 5 times diastolic threshold. Venous ethanol concentrations were measured (HPGC method) every 10 minutes and at the time of arrhythmia induction. Atrial tachvarrhythmias were induced in 4 of 9 baseline RASPs, and lasted for a mean of 21 seconds, and in 16 of 71 RASPs after alcohol lasting for a mean of 357 seconds. Only fib- rillation was observed at the baseline RASP. The atrial tachyarrhythmias induced after alcohol were AF in 1 RASPs and atrial flutter in 5 RASPs (in 5 animals). The mean venous ethanol concentration at the time of the longest arrhythmia induced for each RASP were 200 $ 89 mg/dL for RASP inducing fibrilla- tion and 292 ≤40 mg/dL for RASP inducing flutter (P < 0.05). Flutter tended to be sustained (> 1 minute in duration) more often than fibrillation (4 of 5 flutter vs 2 of 1 fibrillation P < 0.05). In three experiments, atrial flutter persisted for >10 minutes and was terminated by overdrive atrial pacing. We concluded: (1) in this closed-chest porcine model, an ethanol infusion facilitates a variety of atrial arrhythmias related to the ethanol concentration; (2) flutter tended to be sustained, and its termination by overdrive pacing suggests the possibility of an alcohol induced reentrant mechanism; and (3) the higher concentration re- quired for atrial flutter, exceeding that usually seen in humans, may help to explain the rarity of atrial flutter in clinical alcohol intoxication. (PACE 1996; 19(Pt. II):1962-1967)