Alcohol consumption has been linked to a reversible form of atrial fibrillation known as Holiday Heart Syndrome, where heavy alcohol intake, dehydration, and elevated stress levels cause the atria of the heart to beat arrhythmically. But good news for the lower chambers of the heart: An observational study in Heart Rhythm's December issue found no link between alcohol and ventricular arrhythmias and a decreased risk of sudden cardiac death with light alcohol use.
The study used data from the UK Biobank, a large biomedical database for public health research, on alcohol consumption in more than 408,000 participants with ventricular arrhythmia and sudden cardiac death over an 11.5 year time span. Outcomes were based on hospitalization and death records. Alcohol consumption was measured as the number of standard drinks per week, with the UK's standard drink equivalent to 8 grams of alcohol. After adjusting for multiple baseline characteristics, no relationship was found between alcohol consumption and ventricular arrhythmia.
Interestingly, light to moderate alcohol consumption was associated with a lower risk of mortality and heart attack compared to abstaining completely and heavy alcohol use. Heavy drinking was associated with a higher risk of sudden cardiac death overall. In this study, consumption of fewer than 26 drinks per week was associated with the lowest risk for sudden cardiac death. Types of alcohol consumed also mattered: red and white wine were associated with reduced risk while beer, cider, and spirits were associated with an increased risk. As mentioned, data were based on the UK's standard measurement of a drink as 8 grams of alcohol. A standard drink in the US contains 14 grams.
Christopher Wong, MBBS, PhD, the study's senior author, cautions, "Data so far suggest different effects of alcohol on different conditions. We think light drinking may reduce the risk of MI, and several other cardiovascular conditions, but we know that it increases the risk of AF." Other studies have suggested that light to moderate drinking increases the risk of breast cancer and high blood pressure but reduces the risk of lymphomas, leukemias and diabetes.
Wong adds, "We can't be sure what is safe, but it is thought that one standard drink per day may be acceptable. Where light drinking becomes moderate drinking is not at all clear. There is not enough good evidence to recommend that non-drinkers start drinking small amounts of alcohol for cardiovascular benefits, and it is quite clear that large amounts of alcohol are harmful."
Researchers state randomized trial studies are needed to further examine alcohol's effects on heart health.