From MD Consult, November 30, 2005

Whether shoveling show, shoveling seconds onto a plate during a holiday party or dealing with emotional stress, December is fraught with perils for people with weak hearts.

A recent Duke University study of nearly 128,000 people found that more heart attacks occur during the holidays, with a higher percentage of fatalities, than at any other time of year.

"There are a variety of reasons, for which there are some data," said Dr Edward Geltman, director of the Heart Failure Program at Barnes-Jewish Hospital and a professor of medicine in the Cardiovascular Division at Washington University School of Medicine, both in St. Louis.

People in colder climates, for instance, are out shoveling snow—strenuous exercise their hearts may not be ready for.

"The association between heart attack and physical exertion in cold weather, like shoveling snow, is very well-described," Dr Geltman said. "What happens there is ... they are increasing their oxygen demand, perhaps in a way they haven''t done for a while, and, at the same time, they are vasoconstricted. The cold weather causes their arteries and their peripheral arteries to clamp down to keep them from losing heat.

"When you vasoconstrict like that, it increases the work of the heart," he said. "So you have a double increase in the work of the heart—in part because of the vasoconstriction, in part because of the physical activity. People who aren''t used to that will sometimes go out and overdo it. ... They expose their hearts to a level of physical stress they''re not used to."

Stressful situations are also well known to bring on heart attacks in people who are susceptible, Dr Geltman said.

"Holiday times are times of stress," he said. "Either people are not with family when they want to be, or they are with family they don''t want to be with. There are financial stresses over the cost of the holidays. There are a whole bunch of emotional stresses that go on. There are a lot of people who remember lost spouses or family members around the time of life cycle events like the holidays. So there''s a whole emotional overlay. There''s fairly extensive literature on the association between emotional events and cardiac events. People who have demonstrated arrhythmias in response to emotional stresses."

Overdoing intake of alcoholic beverages can contribute to heart problems.

"There''s a thing called a holiday heart, which is atrial or ventricle arrhythmias that occur during and shortly after bouts of excessive drinking," Dr Geltman said. "And more of that happens at hoilday parties and that sort of thing. Sometimes it happens in the withdrawal phase from drinking. So someone has been out bingeing over the weekend, and then Monday morning is when they have the arrhythmia."

Alcohol metabolites called fatty acid ethyl esters can damage heart membranes or electrically active cells and can therefore lead to arrhythmias, Dr Geltman said.

"Alcohol is a cardiac toxin," he said.

Overeating has also been shown to be a catalyst for heart attack.

"There''s very good data that acute changes in blood lipids can be associated with changes in coronary artery and other vascular tone," he said. "So, we know that, and there are certain circumstances—certain physiological stimuluses—that will make a normal vessel dilate. That''s called abnormal endothelial function. ... After a fatty meal, endothelial function is reduced, and you don''t get as much vasodilatation. A big, fatty meal may actually contribute to coronary events by decreasing—impairing—endothelial function, which keeps arteries dilated."

Doctors should be proactive when discussing these issues with at-risk patients, Dr Geltman said. Starting in October, remind patients to take it easy during end of the year celebrations and late-season snow storms. There is no reason to shovel snow, he said, when neighborhood children are anxious to do it to make some holiday money. Patients should also be reminded to exercise restraint with holiday food and libations.

"Give people the appropriate precautions about exercising in the cold, about not overdoing it with alcohol and fatty meals, making sure they take their medications," he said. "And if they know it''s going to be their first Christmas without their spouse or their first-born son or whatever, they should make sure to have as much family support around as possible."