Irregular Heartbeat May Speed Memory Loss in Seniors

Study found that people with atrial fibrillation showed mental declines at earlier age than those without heart condition

By Steven Reinberg

HealthDay Reporter

WEDNESDAY, June 5 (HealthDay News) -- Older people who suffer from a type of irregular heartbeat called atrial fibrillation may also be more likely to experience mental declines sooner, a new study suggests.

"Problems with memory and thinking are common for people as they get older," said lead researcher Evan Thacker, a statistician in the department of epidemiology at the University of Alabama at Birmingham. "Our study shows that, on average, these problems may start earlier or get worse more quickly in people who have atrial fibrillation. This means that heart health is an important factor related to brain health."

As with other such studies, this one established only an association between atrial fibrillation and mental decline, not a direct cause-and-effect relationship.

That's why the next step is to find out why people with atrial fibrillation start to struggle with memory and thinking sooner, Thacker said.

There are at least two possibilities, he said. First, people with atrial fibrillation may have small blood clots form in the heart that then become lodged in the brain.

"These may be too small to cause noticeable strokes, but may over time cause small damage to the brain that would eventually lead to mental decline," Thacker said.

Second, people with atrial fibrillation may simply have less blood flowing to the brain, he said.

"This could result in the brain not getting as much oxygen and nourishment as it needs, which could lead to damage over time that would result in mental problems," Thacker said.

"Currently, we do not know whether either of these two possibilities actually occurs," he said. "We would like to study it using brain imaging technology to learn more about what is happening in the brains of people with atrial fibrillation."

Eventually, if doctors and researchers can discover why people with atrial fibrillation show accelerated mental decline, they might be able to learn how to prevent the problem, Thacker said.

The report was published online June 5 in the journal Neurology.

Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles, said, "Atrial fibrillation is present in close to 3 million men and women in the United States and increases the risk of stroke fivefold compared to the general population."

In addition to the marked increase in the risk of stroke, more recent research suggests that atrial fibrillation is associated with an increased risk of mental decline and dementia, he said.

"Repetitive, small subclinical strokes in patients with atrial fibrillation may account for these findings," Fonarow said.

He said giving blood thinners to patients with atrial fibrillation is standard care to prevent clots in the heart from migrating to the brain.

Putting these patients on anticoagulants, such as warfarin or one of the newer therapies, will "likely be effective in not only reducing the risk of stroke, but also reducing the significant risk of mental decline and dementia," he said.

View the original article here

Antidepressants Celexa, Lexapro Tied to Irregular Heartbeat: Study

TUESDAY, Jan. 29 (HealthDay News) -- People taking certain antidepressants, including Celexa and Lexapro, may have a slightly increased risk of developing an abnormal heart beat.

Researchers say the drugs, which are in a class of medications called selective serotonin reuptake inhibitors (SSRIs), may extend the length of electrical activity in the heart, called a QT interval. A long QT interval is an indicator of abnormal heart rhythms.

"For people who are taking higher doses of citalopram (Celexa) or escitalopram (Lexapro), they should discuss these doses with their doctors," said lead researcher Dr. Roy Perlis, director of the Center for Experimental Drugs and Diagnostics in the psychiatry department at Massachusetts General Hospital in Boston.

"They should absolutely not just stop their medicine," he added.

QT interval is just one indicator of cardiac risk, so there are many other factors to consider in choosing a depression treatment, Perlis said. "It's important to know that there are other medicines which appear to be safe in terms of effects on heart rhythm," he added.

The report was published in the Jan. 29 online edition of the journal BMJ.

Doctors use an electrocardiogram (ECG) to measure the QT interval. The interval varies with heart rate, lengthening when the heart beats slower and shortening when the heart beats faster.

The normal QT interval for men is less than 420 milliseconds and for women it is less than 440 milliseconds. When the timing gets longer, the risk for abnormal heart rhythms increases, the researchers noted.

The U.S. Food and Drug Administration warned recently that Celexa and drugs like it could cause this problem.

To shed light on the matter, Perlis' team collected data on more than 38,000 adults who had an ECG after using antidepressants or methadone between February 1990 and August 2011. They found patients taking Celexa, Lexapro, Elavil (amitriptyline) and methadone had a small but significantly longer QT interval. This effect grew as dosage increased, they noted.

Nearly one in five patients taking these drugs had longer QT intervals, the study found. Whether this effect is clinically significant, however, isn't known.

"For people who need to take antidepressant doses higher than 40 milligrams of citalopram, there are a number of safe alternatives," Perlis said.

Other antidepressants were not associated with longer QT intervals. In one case, the opposite occurred.

"To our surprise, we also found that another antidepressant, bupropion (Wellbutrin, Zyban), actually shortens QT interval, though we don't know whether this is beneficial or just another indication that it is safe from a cardiac perspective," he said.

In the study, the researchers took other risk factors into account, such as age, race, sex, history of depression, heart attack, high blood pressure, heart rhythm problems and pre-existing conditions. They included methadone because it is also known to cause a longer QT interval.

View the original article here