If you've ever had a heart flutter that wasn't caused by romance, take note: People under 70 with atrial fibrillation are 130 percent more likely to develop Alzheimer's disease than those without it.

That's according to researchers at Intermountain Medical Center, who are presenting their findings today to thousands of heart specialists during the annual meetings of the Heart Rhythm Society in Boston.

Dr. T. Jared Bunch, an IMC cardiologist and lead researcher, said the study includes data from more than 37,000 Intermountain Healthcare patients. "To our knowledge, this is the first large-population study to clearly show that having atrial fibrillation puts patients at greater risk for developing Alzheimer's disease."

While the known risk factors for Alzheimer's are genetics, age and family history, heart health has long been suspected to play a role but has not been directly linked to the disease, he said. The new study bolsters that connection.

"I wouldn't call it predictive. We can't say that atrial fibrillation causes Alzheimer's, but we can say those with AF (atrial fibrillation) are at higher risk, and once they get it, the combined disease state worsens outcomes significantly," Bunch said.

Researchers were surprised, he said, that "the youngest patients were at highest risk. It suggests that AF is playing a role in the risk compared to other factors in aging."

Atrial fibrillation is an irregular and often rapid heart rate, and can cause heart palpitations, chest discomfort, shortness of breath and weakness. It is often caused by high blood pressure, sleep apnea or heart disease and leads to blood pooling in the heart, where it can clot and cause a stroke.

According to the American Heart Association, about 2.2 million Americans have been diagnosed with the disorder, which is the most common heart rhythm problem. In people with the disorder, the heart's two small upper chambers quiver instead of beating effectively, allowing blood to pool and even clot.

Early, aggressive treatment of high blood pressure and sleep apnea can either reduce or eliminate AF in some patients, Bunch said. Atrial fibrillation episodes can come and go, and in some cases, people are not even aware their heart is beating irregularly, a condition called "silent" AF.

"When it comes and goes, it's much more responsive to medications and ablative therapies," he said, adding that once AF becomes chronic, the effectiveness of treatment decreases.