Moderate Drinking May Not Affect Chance of Repeat Heart Attack, Study Finds

The researchers found that light-to-moderate alcohol consumption neither helped nor hurt recovery from heart failure.

Jacob Gaffney
Posted: September 3, 2004

People who have suffered heart attacks may require a lifestyle change -- better diet, more exercise -- in order to help the heart heal. But giving up a glass or two of wine with dinner is not necessary, according to a recent study by a team of researchers from medical centers across the United States and Canada.

Some prior studies in the United States and France have shown that moderate drinking may be linked to a reduced risk of a repeat heart attack. But other studies indicate that heart-attack survivors should abstain from alcohol, and the American Heart Association's current guidelines state that people at risk of heart failure should abstain from alcohol.

In the research published earlier this summer in the Journal of the American College of Cardiology, the authors wrote that they wanted to determine if alcohol indeed should be avoided after heart failure "as several studies have shown that major clinical improvement and normalization of left ventricular function can be achieved after abstention."

In some cases, heart attacks may leave patients with a condition called left ventricular systolic dysfunction. Normally, in order to pump blood, areas of the heart squeeze in a synchronized way. The upper chambers, the atria, contract first, and then the bottom two chambers, the ventricles, contract. Heart attacks can sometimes damage the way the left ventricle works, making proper pumping laborious. This lowers the amount of blood the heart pumps when it contracts, known as systolic blood pressure. This condition can lead to another instance of heart failure.

To examine the effects of drinking on people with left ventricular systolic dysfunction, the scientists pulled data from the Survival and Ventricular Enlargement (SAVE) trial, which took place from 1987 to 1992 at 45 medical centers in the United States and Canada. The purpose of that study was to test if certain enzyme inhibitors would lower the blood pressure of heart-attack survivors. All participants suffered from left ventricular systolic dysfunction.

The researchers examined data from 2,231 male and female patients, aged 21 to 80, who were adminstered placebos instead of the enzyme inhibitors. During clinic visits, health factors such as smoking status, body mass index and history of diabetes were recorded, and the amount of blood the left ventricular pumps out per beat was measured.

The patients also provided information on their alcohol consumption for the three months leading up to the heart attack (anyone who changed habits during that time was excluded) and the three months following it. Thereafter the patients reported their drinking habits every six months for two years. Those participants were broken down into categories: nondrinkers, light-to-moderate drinkers (one to 10 drinks per week) and heavy drinkers (more than 10 per week). Many of the patients gave up drinking immediately after their heart attacks, and three months later, nondrinkers made up 71 percent of the study group, light-to-moderate drinkers made up 26 percent and heavy drinkers 3 percent.

(The study's definitions of moderate and heavy are slightly lower than those in some other research and in the U.S. Dietary Guidelines, which define moderate consumption for men as up to two drinks a day. This study did not define how much alcohol is in a drink, but other research typically describes one drink as a shot of liquor, a 4- to 5-ounce glass of wine or 12 ounces of beer.)

During the course of the SAVE study, a total of 456 patients experienced another instance of heart failure, and 195 patients died from this or other causes. When the researchers compared the patients with their post-heart attack drinking habits, they found "the crude incidence of heart failure was 22.5 percent in nondrinkers, 16.6 percent in light-to-moderate drinkers, and 21.3 percent in heavy drinkers," the authors wrote.

But after adjusting for all other health factors and changes in drinking habits, "the risk of developing heart failure was similar in the three groups," the authors wrote. Three months after their heart attacks, the light-to-moderate drinkers had a 3 percent lower risk of heart failure than the nondrinkers, within the statistical margin of error. Heavy drinkers showed a 22 percent greater chance of heart failure than nondrinkers. But two years after their heart attacks, the risks had leveled off, and "no statistically significant benefit or hazard was seen in heavy drinkers." The scientists noted that those results may be less accurate because heavy drinkers were such a small percentage of the group.

Light-to-moderate drinkers were at no greater risk for a second heart attack than nondrinkers, indicating that it's not necessary to abstain from alcohol after heart failure. But the researchers concluded that alcohol consumption "was neither beneficial nor detrimental" in recovery after a heart attack.

For a comprehensive look at the potential health benefits of drinking wine, check out senior editor Per-Henrik Mansson's feature Eat Well, Drink Wisely, Live Longer: The Science Behind A Healthy Life With Wine

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