Atrial fibrillation (AF) is the most common heart arrhythmia seen clinically, but until now research has largely focused on risk factors for developing the disease and therapies to treat it, rather than factors that determine when and where an episode might occur. AF can lead to loss of quality of life, significant health care costs, stroke and death.
Large studies have shown that chronic alcohol consumption can be a predictor of the condition, and Marcus and other scientists have demonstrated that it is linked to heightened risks of a first diagnosis of atrial arrhythmias.
The research centered on 100 patients with documented AF who consumed at least one alcoholic drink a month. The patients were recruited from the general cardiology and cardiac electrophysiology outpatient clinics at UCSF. People with a history of alcohol or substance use disorder were excluded, as were those with certain allergies, or who were changing treatment for their heart condition.
Each wore an electrocardiogram (ECG) monitor for approximately four weeks, pressing a button whenever they had a standard-size alcoholic drink. They were also all fitted with a continuously recording alcohol sensor. Blood tests reflecting alcohol consumption over the previous weeks were periodically administered. Participants consumed a median of one drink per day throughout the study period.
Researchers found that an AF episode was associated with two-fold higher odds with one alcoholic drink, and three-fold higher odds with two or more drinks within the preceding four hours. AF episodes were also associated with an increased blood alcohol concentration.
The authors note study limitations, including that patients might have forgotten to press their monitor buttons or that they minimized the number of button presses due to embarrassment, although these considerations would not have affected alcohol sensor readings. Additionally, the study was limited to those with established AF, not to the general population.
“The effects seem to be fairly linear: the more alcohol consumed, the higher the risk of an acute AF event,” said Marcus. “These observations mirror what has been reported by patients for decades, but this is the first objective, measurable evidence that a modifiable exposure may acutely influence the chance that an AF episode will occur.”