Alcohol and vagal activation as AF trigger

SAN FRANCISCO, CALIFORNIA. There is evidence that alcohol consumption, especially binge drinking, often precedes that very first atrial fibrillation (AF) episode. Two studies specifically surveying paroxysmal afibbers found that 22% to 34% reported that alcohol consumption preceded their first episode. The question naturally arises is alcohol consumption also a trigger for future episodes? A group of electrophysiologists (EPs) at the University of California now confirms that alcohol consumption is indeed a trigger, especially in younger afibbers with the vagal variety of AF.

Their study included 133 participants with documented, mostly lone, paroxysmal atrial fibrillation (PAF) and 90 controls with various documented forms of supraventricular tachycardia (SVT) with 56% having atrioventricular nodal re-entrant tachycardia (AVNRT), 27% having atrioventricular re-entrant tachycardia (AVRT), and 16% having atrial tachycardia (AT). One hundred and ten patients with PAF (83% of a total AF sample) and 68 patients with SVT (76% of total SVT sample) answered questions as to how frequently alcohol provoked their episodes. After adjusting for potential confounders, the researchers concluded that PAF patients were 4.4 times more likely to report alcohol as a trigger than were those with SVT. Seven percent of afibbers reported that alcohol always or often triggered an episode, while only 1% in the SVT group reported an association. By far, the worst offender was beer.

The California EPs also investigated the association between activation of the vagal (parasympathetic) arm of the autonomic nervous system and the triggering of an AF or SVT episode. Overall, 50% of the 221 respondents reported that vagal activities (resting, sleeping, eating, and symptoms that terminated with exercise) precipitated their episodes. However, vagal activation was twice as likely to trigger episodes in PAF patients than in SVT patients. Younger age and a family history of AF were markedly associated with having vagal triggers. There was a strong correlation between having alcohol and vagal activities as triggers, with afibbers reporting alcohol as a trigger also reporting vagal activities as a trigger. The researchers speculate that alcohol may trigger AF through vagal activation or that the electrophysiologic effects (shortening of action potential duration and refractory period) of alcohol consumption and vagal activation are similar.

Activation of the adrenergic (sympathetic) arm of the autonomic nervous system (physical overexertion, emotional stress and caffeine consumption) was associated with the triggering of arrhythmias in 40% of cases, with no significant difference between PAF and SVT patients.
Mandyam, MC, et al. Alcohol and vagal tone as triggers for paroxysmal atrial fibrillation. American Journal of Cardiology, April 20, 2012 [Epub ahead of print]

Editorís comment: Our very first LAF Survey (February 2001) identified the following important triggers of AF episodes:

  • Emotional or work-related stress - 50%
  • Physical overexertion - 24%
  • Alcohol consumption - 22%
  • Resting - 22%
  • Heavy meals - 18%
  • Caffeine consumption - 16%

Later surveys associated the initiation of vagal episodes with alcohol consumption (33%), resting/sleeping (33%), heavy meals (28%), and fatigue and lack of sleep (36%). The most important triggers for adrenergic episodes were stress and anxiety (94%), exercise (44%), specific foods and food additives (38%), and caffeine (31%).