As older folks are wont to say, "If it's not one thing it's another" — and sometimes it's both.

A common type of irregular heartbeat, called atrial fibrillation, may be linked to a higher likelihood of developing problems with memory and thinking, researchers reported.

Investigators at the University of Alabama, Birmingham followed more than 5,000 elderly people from four communities in the United States who were enrolled in a heart study for approximately seven years. At the beginning of the study, none of the participants had a history of atrial fibrillation or stroke, though researchers excluded those who later developed stroke from their analysis.

Among those participants, one in 10 developed atrial fibrillation during the study. Every year, researchers measured the elderly people on a 100-point memory and thinking test.

"Problems with memory and thinking are common for people as they get older. Our study shows that on average, problems with memory and thinking may start earlier or get worse more quickly in people who have atrial fibrillation," Evan L. Thacker, Ph.D., lead study author, told media. "This means that heart health is an important factor related to brain health."

The most common type of cardiac arrhythmia, atrial fibrillation, is associated with heart palpitations, fainting, and congestive heart failure. The condition increases the risk of stroke, sometimes substantially, depending on other risk factors such as hypertension. In those with the condition, the normal electrical impulses from the sinoatrial node are overwhelmed by other electrical impulses, which usually come from the roots of the pulmonary veins.

Those with atrial fibrillation were more likely to score lower on memory and thinking scores at earlier stages, compared to those without the condition. Among those 80-85 years of age, the average score on the test fell by approximately six points for those without the condition. Those with atrial fibrillation scored 10 points lower than previously — a significantly heightened mental decline.

In the 75 and older age range, the average rate of decline was approximately three to four points greater every five years for those with the condition, compared to those without atrial fibrillation.

"This suggests that on average, people with atrial fibrillation may be more likely to develop cognitive impairment or dementia at earlier ages than people with no history of atrial fibrillation," Thacker said.

On the 100-point test, scores below 78 were deemed suggestive of dementia, researchers said. Without the condition, most people would decline to that level by age 87 — but those with atrial fibrillation experienced that borderline dementia two years earlier.

"If there is indeed a link between atrial fibrillation and memory and thinking decline, the next steps are to learn why that decline happens and how we can prevent that decline," Thacker said.

 

Source: Thacker EL. Rapid, Irregular Heartbeat May Be Linked To Problems With Memory And Thinking. Neurology. 2013.