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.