FRIDAY, Sept. 7 (HealthDay News) -- Patients with atrial fibrillation -- a heart rhythm disorder -- are increasingly aware of the link between their condition and the increased risk of stroke, according to a recent survey.

Atrial fibrillation is a quivering or irregular heartbeat that affects about 2.7 million people in the United States.

A 2011 survey of more than 500 people with atrial fibrillation found that half of them were unaware they had a fivefold increased risk of suffering a stroke. But the more recent American Heart Association/American Stroke Association 2012 poll of 500 people with atrial fibrillation found that 64 percent knew about this level of increased stroke risk.

The improved awareness "is a great step in the right direction," association spokesperson Dr. Patrick Ellinor, associate professor at Harvard Medical School and a cardiologist at Massachusetts General Hospital in Boston, said in an AHA/ASA news release.

"The American Heart Association/American Stroke Association works to provide health care providers, patients and caregivers the educational tools and resources they need on this very important topic," Ellinor added. "We hope to report a higher percentage annually until we reach 100 percent."

The 2012 survey also found that 82 percent of respondents believe having atrial fibrillation increases their stroke risk, compared with 75 percent in the 2011 survey.

Many atrial fibrillation patients rely on their health care providers for information about their condition and education about its health risks, the release noted. The recent survey found that two-thirds of patients have discussed their risk for stroke with their health care provider, but only about one-third were told they are at high risk for stroke.

More information

The U.S. National Heart, Lung, and Blood Institute has more about atrial fibrillation.

THURSDAY, Sept. 6 (HealthDay News) -- While some say it's not as flavorful as the real thing, drinking nonalcoholic red wine might help lower blood pressure in men at high risk for heart disease.

Middle-aged and older men who drank moderate amounts of de-alcoholized red wine daily for four weeks had drops in systolic (top number) and diastolic (bottom number) blood pressure, according to a small new study by Spanish researchers.

"In the context of a healthy diet and a healthy lifestyle, daily consumption of de-alcoholized red wine can help prevent hypertension," said study author Gemma Chiva-Blanch, at the department of internal medicine at the Hospital Clinic of Barcelona.

The study was published online Sept. 6 in the journal Circulation Research.

The nonalcoholic wine drinkers also showed increased levels of nitric oxide -- a molecule in the blood that previous studies have linked with improving blood-vessel health and lowering blood pressure.

While some studies have shown that moderate alcohol consumption lowers the risk of cardiovascular disease, others suggest red wine in particular is beneficial, possibly because it's rich in polyphenols, which are antioxidants linked with lowering blood pressure.

Though it is well-documented that binge and heavy drinking are bad for blood pressure, the effect of moderate alcohol consumption has been unclear, the authors said.

The study "compares the effects of red wine and a nonalcoholic red wine with identical composition -- except for the alcohol content -- in the same subjects," Chiva-Blanch said. The scientists also analyzed gin's effect.

Participants were 67 men aged 55 or older who either had type 2 diabetes or more than three risk factors for cardiovascular disease, such as smoking, high blood pressure, high cholesterol, being overweight or obese, or a family history of premature coronary heart disease.

After an initial two-week abstinence period, they were separated into three groups assigned to a different beverage: three ounces of gin, 10 ounces of red wine or 10 ounces of nonalcoholic red wine. After four weeks of daily consumption, the men rotated to a new beverage, and so forth with the third beverage.

After each rotation, researchers measured blood pressure, heart rate, and nitric oxide levels in the blood, and then a statistical analysis was performed.

They found a reduction in blood pressure after the men drank red wine but it was not statistically significant, and gin consumption did not reduce blood pressure. However, after the men drank the alcohol-free red wine, blood pressure levels dropped significantly. Systolic blood pressure levels decreased by about 6 mmHg, and diastolic blood pressure levels dropped by 2 mmHg.

In theory, the authors said those changes could reduce the risk of heart disease by 14 percent and cut the chance of a stroke almost 20 percent.

Mayo Clinic cardiologist Dr. Sharonne Hayes said the new research is "a hypothesis-generating study" that needs more investigation.

"Gin, Mai Tais, wine, beer -- a lot of studies would suggest that when it all comes down to it, it's the alcohol. But then there was a rise of interest in polyphenols -- resveratrol in red wine and grapes. But most of those studies showed that giving polyphenols by themselves showed no benefit or change. So the thinking has circled back to maybe it's just the alcohol," Hayes said.

She noted that the study was small, with no control group. She said it's known that blood pressure goes up when alcohol is withdrawn, even if the person is not a heavy drinker, and she speculated that the two-week "wash-out" period before the study could have influenced the results.

"So I have problems with the methods in this study. It's intriguing; it's suggestive, but not definitive. It needs to be explored. The methods may not be enough to allow us to extrapolate this to say that alcohol or de-alcoholized wine is better for you," Hayes said, adding that lowering blood pressure for a few weeks also doesn't indicate that cardiovascular risk will decrease long-term. "But to be fair, the authors say this, too," she added.

American Heart Association president Donna Arnett said the research is interesting because it looks at a specific type of drinking.

"This is that in-between phase of solidly moderate drinking. So in that way it offers something new," said Arnett, who is also an epidemiologist at the University of Alabama at Birmingham.

While the research holds promise, Arnett said she is concerned about the methodology. She noted, "They didn't have a 'wash-out' period between the interventions and that's important because it lets people stabilize and return to their blood pressure value before the intervention. It is possible that there is a carryover effect from one of the drinking periods to the next. That had me concerned from a study-design perspective."

Hayes said it would be intriguing to study other groups: a mixed-sex group, a younger group including patients with lower risk factors and women in perimenopause.

"High blood pressure is an important issue in women. And we now know there are sex differences in responses to alcohol intake," Hayes said.

The authors of an editorial that accompanies the study said there is growing evidence that the chemicals in red wine confer health benefits beyond alcohol, and the new research adds to it.

"However, numerous issues need to be resolved in order to clearly assess the preventive or therapeutic potential of red wine constituents," wrote Huige Li and Ulrich Forstermann, with the department of pharmacology at Johannes Gutenberg University Medical Center in Mainz, Germany.

Chiva-Blanch noted that while this study showed de-alcoholized red wine seems to have "exclusive" effects in blood pressure, "when talking about other cardiovascular risk factors such as low HDL cholesterol, de-alcoholized red wine has no effects."

She also pointed out that other research shows red wine consumption has protective effects in atherosclerosis and cholesterol.

Would people be willing to swap their cabernets and Chiantis for an alcohol-free version, if the health benefits were confirmed?

Mayo Clinic's Hayes isn't sure. She said nonalcoholic red wine lacks the body and fullness of real red wine.

"People drink for other reasons that are complex and personal -- whether it's how you feel or it's about the complex taste. If we found that drinking de-alcoholized red wine was truly therapeutic, that it actually lowered blood pressure, I think people would probably take it as medicine," Hayes said.

Chiva-Blanch said, "It depends on the health awareness of the population. People who care about their health would be willing to switch to nonalcoholic drinks, while others would not."

More information

Visit the U.S. Centers for Disease Control and Prevention to learn more about alcohol and public health.

TUESDAY, Sept. 4 (HealthDay News) -- Far more older people than thought may suffer heart attacks that are never diagnosed, a new study suggests.

These so-called "silent heart attacks" can increase the risk of dying as much as any confirmed heart attack does, the researchers added.

To reach their conclusion, the study authors used sophisticated MRI scans to spot heart trouble among more than 900 older Icelanders between the ages of 67 and 93.

"MRI scanners are really a spectacular tool for finding heart disease," explained lead researcher Dr. Andrew Arai, chief of the cardiovascular and pulmonary branch at the U.S. National Heart, Lung, and Blood Institute.

However, people shouldn't be running out to get scanned, he stressed: "I wouldn't recommend that. Most guidelines don't recommend having these expensive tests unless you are having symptoms."

Right now, it isn't clear when such scans are called for and who would benefit from them, Arai noted, although this latest finding is a first step toward determining that.

The report was published in the Sept. 5 issue of the Journal of the American Medical Association.

Among the more than 900 Icelanders studied, 91 had heart attacks that had been diagnosed, while 157 had heart attacks that had not been recognized before, the researchers found. Cardiac MRI detected more cases of unrecognized heart attack in people with diabetes (21 percent) than in those without diabetes (14 percent), the researchers added.

Over more than six years of follow-up, 33 percent of those who had recognized heart attacks died, as did 28 percent of those with unrecognized heart attacks, which was significantly more than the 17 percent who died among those who had never had a heart attack, the researchers noted.

Not surprisingly, significantly more people who had a recognized heart attack were taking beta blockers to lower blood pressure and statins to lower cholesterol than people who had an unrecognized heart attack.

In fact, about half of those with an unrecognized heart attack were taking aspirin, but less than half were taking beta blockers or statins. This may well have added to their risk of having a heart attack, the researchers suggested.

The greater number of unrecognized heart attacks may be due to several factors, including diabetes, which raises the risk of a heart attack, milder symptoms and a less severe attack, the study authors noted.

Although the study was done in Iceland, Arai said he believes the results would be similar in the United States.

Commenting on the study, Dr. Gregg Fonarow, a spokesman with the American Heart Association and a professor of cardiology at the University of California, Los Angeles, said: "Prior studies have demonstrated that a portion of myocardial infarctions [heart attacks] are not detected clinically, or are so-called 'silent myocardial infarctions.'"

Cardiac MRI is a very sensitive approach for detecting heart attacks, he added.

"This study found a higher prevalence of previously unrecognized heart attacks than described in prior studies," Fonarow said. "Silent heart attacks have a similar adverse long-term prognosis as clinically recognized heart attacks."

Fonarow, however, doesn't think cardiac imagining is useful yet as a screening tool to find people at risk for a heart attack or to diagnose an unrecognized heart attack.

"At this point in time, there is not sufficient evidence on which to recommend cardiac imaging as a screening test. Further studies are necessary," he said.

More information

For more information on heart attack, visit the American Heart Association  .

TUESDAY, Sept. 4 (HealthDay News) -- Exposure to a chemical used in some common household products may be associated with heart troubles and peripheral artery disease, a new study suggests.

The chemical perfluorooctanoic acid (PFOA) -- which is widely used to make products such as food packaging, paper and textile coatings, polishes and lubricants -- is detectable in the blood of more than 98 percent of people in the United States, according to previous research.

In this study, a team at the West Virginia University School of Public Health looked at data from more than 1,200 people and found that increasing blood levels of PFOA were associated with the presence of heart and artery disease.

This association appeared to be independent of other disease risk factors such as age, sex, race/ethnicity, smoking, body-mass index, diabetes, high blood pressure and cholesterol levels.

The study was published online Sept. 3 in the Archives of Internal Medicine.

"Our results contribute to the emerging data on health effects of PFCs [perfluoroalkyl chemicals], suggesting for the first time that PFOA exposure is potentially related to [cardiovascular and peripheral artery disease]. However, owing to the cross-sectional nature of the present study, we cannot conclude that the association is causal," wrote Dr. Anoop Shankar and colleagues.

Further research is needed to confirm or disprove the findings, they added. While the study found an association between PFOA exposure and vascular diseases, it did not prove a cause-and-effect link.

Cardiovascular disease is a major health problem in the United States and identifying new risk factors for the disease, including exposures to chemicals, is important, the researchers noted.

More information

The U.S. National Heart, Lung, and Blood Institute has more about heart and vascular disease.