By Andrew M. Seaman
NEW YORK (Reuters Health) - People with an irregular heartbeat may also be at increased risk of being depressed, suggests a new study from Germany.
The added risk was small, researchers found, but it's in keeping with other studies linking heart disorders with depression.
"It's consistent with a large and growing literature on the role that depression plays with heart disease," Richard Sloan, who was not involved with the new study, said.
Sloan is the Nathaniel Wharton Professor of Behavioral Medicine in the Department of Psychiatry at Columbia University in New York.
"There are a great set of studies, many of which show a much stronger effect," he told Reuters Health.
Atrial fibrillation (AF) is a type of rhythm disorder affecting the heart's upper chambers. It can be caused by a number of issues - including heart attacks, infections and heart valve problems. Obesity is a risk factor for AF, as are high blood pressure, high cholesterol and diabetes.
Approximately five million people in the U.S. were diagnosed with AF in 2010. That number is expected to grow to about 12 million new cases per year by 2030, according to one recent study (see Reuters Health story of Jul 26, 2013 here:).
Doctors have long known that patients' mental state can affect how well they take care of themselves, follow treatment instructions and how they perceive the burden of their illnesses.
Dr. Renate Schnabel, from the University Heart Center in Hamburg, and her fellow researchers wanted to see if depression might affect the course of atrial fibrillation and patients' feelings about their disease.
Schnabel's team used data on 10,000 German adults for the new study. Most did not have AF, but 309 did.
The researchers compared the average depression scores for people with AF to the scores of people without the condition.
Depression was measured on a scale of zero to 27, with higher scores indicating more severe depression.
On average, people with AF scored a four, compared to an average score of three among those without the irregular heartbeat. In either group's case, the score wouldn't be enough to warrant treatment for depression.
Sloan said a one-point difference in depression severity wouldn't be noticeable to an individual. The study also can't answer whether one condition leads to the other or if they simply share a common cause, he said.
Schnabel and her colleagues did find that the difference in depression severity they saw was mostly driven by the physical symptoms of depression, such as aches and pains, being more common or intense in people with irregular heartbeats.
Screening for and treating depression symptoms might help heart patients to feel better physically and potentially even improve their heart conditions, the researchers write in PLOS ONE.
Sloan said cardiologists have learned that depression is a condition they should look for and possibly refer their patients for treatment.
"It's a serious matter and should be treated as a serious matter," he said.
"If you're depressed at any time - whether after heart disease or something else - you should treat it."
SOURCE: http://bit.ly/II1jiP PLOS ONE, online December 4, 2013.