Small studies have pointed to the possibility of "adrenergically mediated" atrial fibrillation and indicate drugs can alter the atria's electrical circuitry. But whether atrial fibrillation can be triggered by emotional arousal has been unknown. Researchers sought answers in a prospective, controlled, electronic diary-based study of emotions preceding atrial fibrillation in 75 patients (average age 58, 60 percent male, 60 percent on beta-blockers) with a history of paroxysmal or persistent atrial fibrillation.

They found:

• One hundred nineteen atrial fibrillation episodes in 23 subjects.
• The likelihood of an atrial fibrillation episode was increased by negative emotions and decreased by happiness, whether reported immediately preceding an episode or the night before.
• Anger increased the odds of subsequent atrial fibrillation for men, as did worry for women.
• In a "stratified" analysis, emotion triggered atrial fibrillation only in those not taking beta-blockers.

Patients' heart rhythms were recorded at the time of atrial fibrillation symptoms and they completed diary entries querying mood states for the 30 minutes preceding atrial fibrillation.

Follow-up continued for one year. Patients also underwent 24-hour Holter monitoring and made diary entries twice per hour. Diaries recorded during sinus rhythm served as controls. Patients' exposure to varied emotions - sadness, anger, stress, anxiety, worry - was compared between pre- atrial fibrillation case and control periods. Emotions recorded in nightly diaries prior to daytime atrial fibrillation were compared to those recorded when no atrial fibrillation occurred.

"Negative emotions can trigger atrial fibrillation, while happiness is protective," researchers said. "Whether interventions aimed at reducing psychological effects of emotional stress may reduce atrial fibrillation requires further study."

The lead author was Rachel J. Lampert, M.D. of Yale School of Medicine.