Heavy drinking damages the heart

By Dr. Liji Thomas, MDDec 18 2019

Drinking too much destroys the liver, as is well known. A new study published in the Journal of the American Heart Association on December 18, 2019, shows that excessive alcohol consumption also damages the heart muscle. This is seen by a rise in the level of certain biological molecules in the blood.

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Harmful effects of excessive alcohol consumption

Drinking too much alcohol can cause several types of cardiovascular disease, including alcoholic cardiomyopathy, heart attack, arrhythmias, stroke, high blood pressure, and death. However, it is not clear how these effects occur.

In general, moderate consumption of alcohol means having up to 2 drinks a day for men, and one a day in women. Of course, the amount of alcohol consumed also depends on the type of liquor. For instance, one drink could mean 12 ounces of beer, 4 ounces of wine, or 1.5 ounces of strong spirit including gin and vodka.

It has long been accepted that excessive drinking is injurious to health. It can raise the level of blood lipids like triglycerides, that is linked to atherosclerosis, the condition in which arteries are narrowed by fatty deposits. This is a prime risk factor for heart attack and stroke. Obesity is another outcome, which can in turn increase the risk of developing diabetes. Hypertension, or high blood pressure, is also likely because of the fat-hardened arteries.

Cardiomyopathy refers to weakening of the heart muscle, and the most common type is dilated cardiomyopathy (DCM). Often caused by alcoholism, it can also be due to ischemic damage (as with heart attacks), hypertension, diabetes, thyroid or liver disease, and certain viral infections as well as HIV. The heart wall is weakened causing the heart to dilate and thin out. This affects the strength of contraction, so that the heart becomes a less effective pump. Fluid backs up in the body, causing swelling of the lower parts of the body, breathlessness, and tiredness. Clots may form in the heart leading to strokes and heart attacks. The stretching of the heart may impair the proper action of the heart valves as well. The natural pacemaker region may also be damaged, causing arrhythmias or irregular pumping rhythm.

The study

In the current study, the researchers linked the degree of alcohol consumption with the heart muscle damage. The following were used as signs of heavy drinking that could harm the heart:

• Drinking six or more shots at a time
• Having a hangover or being drunk
• Requiring a drink as soon as one wakes in the morning
• Personal life affected due to the consequences of drinking
• People close to the individual express concern about the level of drinking

In many cases, the heart damage occurs before any symptoms are felt, and this is referred to as subclinical heart disease. This is reflected, however, as increasing levels of certain molecules in the blood. Using these as biomarkers of heart damage, the researchers looked for this condition in drinkers of varying degree.

The researchers took blood samples from over 2,500 people aged 35-69 years, over the period 2015 to 2018. The samples came from another study called the Know Your Heart study. Most participants in this study came from Arkhangelsk, in Russia, and a few were alcoholics being treated at the Arkhangelsk Regional Psychiatric Hospital.

The researchers classified the participants into different categories, based on their habitual consumption of alcohol. This included those who were non-drinkers, those who drank but had no signs of heavy or harmful drinking, and those who drank heavily and met the above criteria.

The blood samples were tested for three markers of cardiac damage:

• High sensitivity cardiac Troponin T, a heart muscle protein which is released into the circulation when the muscle is damaged: it therefore measures cardiac injury.
• N-terminal pro-B-type natriuretic peptide, a hormone that gives rise to the active form B-type natriuretic peptide, is increased when the heart wall muscle is stretched, and especially with heart failure.
• High sensitivity C-reactive protein (CRP) that is raised in inflammatory conditions.

The findings

• The biomarkers were found to be highest in the hospital patients who were the heaviest drinkers, compared to the drinkers who showed no sign of harmful drinking.
• Troponin-T levels were 10% higher, the natriuretic peptide levels were 47% higher, and CRP was 69% higher in this sample compared to drinkers who did not show signs of harmful drinking.
• In the general population, the problem drinkers had almost 32% higher natriuretic peptide levels compared to those who did not drink heavily.

Implications

The study has its limitations. Most prominent is the fact that most of the participants come from Eastern Europe, specifically the Russian territory in that region, which may mean its outcomes do not reflect those that could be found in other ethnic or racial groups.

The researchers say their study shows that heavy drinking is linked to greater inflammation in the body, which in turn is associated with many health conditions like cardiovascular disease. It helps to confirm that alcohol drinking in excess imposes a heavy ill-health burden on the drinker. They are now using ultrasound to image the heart in real-time, so they can see exactly what kind of damage occurs when the individual is a heavy drinker.