A prospective, controlled, electronic diary–based US study suggests that anger or stress can trigger atrial fibrillation (AF), but use of β-blockers is associated with greatly attenuated risk. The study included 91 patients (mean age 59) with a history of paroxysmal or persistent AF recorded their rhythm on event monitors at the time of AF symptoms and completed a diary entry querying mood states (eg, anger and stress) for the preceding 30 minutes (pre-AF “case period”) for 1 year. Patients also underwent monthly 24-hour Holter monitoring during which they were prompted to complete a diary entry twice per hour. Sixty percent of patients were prescribed β-blockers. A total of 163 symptomatic AF episodes (in 34 patients) and 11,563 Holter-confirmed sinus rhythm control periods had associated diary data. Overall, the likelihood of an AF episode was significantly higher during anger or stress. This effect, however, was significantly attenuated in patients on β-blockers (odds ratio 22.5 for patients not prescribed β-blockers vs odds ratio 4.0 for those prescribed β-blockers). Exclusion of patients on sotalol did not affect findings. Previous studies have demonstrated that beta-blockers can decrease triggering of morning peak in both sudden death and myocardial infarction by other sympathetic stimuli. Source: https://www.heartrhythmjournal.com/