Alcohol use disorders and the heart

Alcohol use is an important preventable and modifiable cause of non‐communicable disease, and has complex effects on the cardiovascular system that vary with dose. Observational and prospective studies have consistently shown a lower risk of cardiovascular and all‐cause mortality in people with low levels of alcohol consumption when compared to abstainers (the ‘J’‐shaped curve). Maximum potential benefit occurs at 0.5 to one standard drinks (7–14 g pure ethanol) per day for women (18% lower all‐cause mortality, 95% confidence interval (CI) = 13–22%) and one to two standard drinks (14–28 g ethanol) per day for men (17% lower all‐cause mortality, 95% CI = 15–19%). However, this evidence is contested, and overall the detrimental effects of alcohol far outweigh the beneficial effects, with the risk of premature mortality increasing steadily after an average consumption of 10 g ethanol/day. Blood pressure (BP) is increased by regular alcohol consumption in a dose‐dependent manner, with a relative risk for hypertension (systolic BP > 140 mm Hg or diastolic > 90 mm Hg) of 1.7 for 50 g ethanol/day and 2.5 at 100 g/day. Important reductions in BP readings can be expected after as little as 1 month of abstinence from alcohol. Heavy alcohol consumption in a binge pattern is associated with the development of acute cardiac arrhythmia, even in people with normal heart function. Atrial fibrillation is the most common arrhythmia associated with chronic high‐volume alcohol intake, and above 14 g alcohol/day the relative risk increases 10% for every extra standard drink (14 g ethanol). Ethanol and its metabolites have toxic effects on cardiac myocytes, and alcoholic cardiomyopathy (ACM) accounts for a third of all cases of non‐ischaemic dilated cardiomyopathy. Screening people drinking alcohol above low‐volume levels and delivering a brief intervention may prevent the development of cardiovascular complications. Although people with established cardiovascular disease show improved outcomes with a reduction to low‐volume alcohol consumption, there is no safe amount of alcohol to drink and patients with ACM should aim for abstinence in order to optimize medical treatment.