Kidney Disease May Boost Risk of Abnormal Heartbeat

Dennis Thompson wrote . . . . . . .

People with failing kidneys are at increased risk of developing a life-threatening abnormal heart rhythm, a new report suggests.

Chronic kidney disease can as much as double a patient’s risk of atrial fibrillation, a quivering or irregular heartbeat that can lead to stroke or heart failure, said lead researcher Dr. Nisha Bansal. She is an associate professor of nephrology at the University of Washington’s Kidney Research Institute, in Seattle.

The risk of atrial fibrillation increases as kidney function declines, Bansal said.

“We saw the worse your kidney function, the greater your risk of developing atrial fibrillation. Even mild changes in kidney function were strongly linked to atrial fibrillation,” Bansal noted.

The study included data gathered from three separate research projects focused on heart health in the United States. The three projects created a combined pool of almost 17,000 patients with follow-up periods averaging between 8.5 years and 12.5 years. None of the participants had atrial fibrillation when first recruited.

Each project checked participants’ kidney function when they first joined the study, using one or two different lab tests. One was a blood test that evaluated how well the kidneys were removing toxins from the bloodstream. The other was a urine test that assessed whether the kidneys were properly filtering out a specific protein.

People with worse kidney function at the start of the study were more likely to have atrial fibrillation by the end, the researchers found. Those who did worse on the blood test were twice as likely to develop an abnormal heart rhythm, while those who did worse on the urine test were 76 percent more likely.

While the association doesn’t prove a cause-and-effect relationship, the link remained even after the researchers took into account other risk factors for atrial fibrillation, such as diabetes, tobacco use and a history of heart problems.

“We found that kidney function was independent of all other risk factors,” Bansal said.

Research has not yet been conducted to explain the association between kidney function and atrial fibrillation, Bansal noted, but there are a number of possible explanations.

A poorly functioning kidney can alter blood levels of a number of nutrients needed to maintain proper heart function, such as potassium, vitamin D, calcium and phosphorus, Bansal said.

The kidneys also are responsible for maintaining a steady volume of blood in your body, removing excess fluid by way of urination.

“If your kidney function is impaired, your blood volume increases,” Bansal said. “That increased stress on your heart causes it to stretch and can also trigger this abnormal heart rhythm.”

Dr. Kevin Chan, a nephrologist with Massachusetts General Hospital in Boston, noted that it’s also possible toxins that haven’t been filtered from the blood — thanks to a bad kidney — might have some as-yet-unknown effect on heart function.

Based on this report, doctors treating patients with kidney disease should keep an eye out for potential heart problems, said Chan, who was not involved with the new study.

“Physicians should be cognizant of this relationship so they are attuned to recognizing atrial fibrillation when they see their chronic kidney disease patients,” Chan said.

Doctors can reduce a person’s risk of stroke from atrial fibrillation by putting them on blood thinners, he added. Atrial fibrillation patients also can be fitted with a pacemaker, or undergo a procedure to restore proper heart rhythm.

People with kidney disease could help themselves by adopting a heart-healthy lifestyle, Bansal suggested, for example, eating right, exercising and quitting smoking.

“A heart-healthy lifestyle does improve your risk of all kinds of cardiovascular disease, as well as kidney disease, so I would recommend that,” Bansal advised.

The report was published online in the Clinical Journal of the American Society of Nephrology.

Source: HealthDay

Long Working Hours Increases the Risk of Developing Atrial Fibrillation

People who work long hours have an increased risk of developing an irregular heart rhythm known as atrial fibrillation, according to a study of nearly 85,500 men and women published in the European Heart Journal today (Friday).

The study showed that, compared to people who worked a normal week of between 35-40 hours, those who worked 55 hours or more were approximately 40% more likely to develop atrial fibrillation during the following ten years. For every 1000 people in the study, an extra 5.2 cases of atrial fibrillation occurred among those working long hours during the ten-year follow-up.

Professor Mika Kivimaki, director of the Whitehall II Study, from the Department of Epidemiology at University College London (UK), who led the research, said: “These findings show that long working hours are associated with an increased risk of atrial fibrillation, the most common cardiac arrhythmia. This could be one of the mechanisms that explain the previously observed increased risk of stroke among those working long hours. Atrial fibrillation is known to contribute to the development of stroke, but also other adverse health outcomes, such as heart failure and stroke-related dementia.”

Prof Kivimaki and colleagues from the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium analysed data from 85,494 men and women from the UK, Denmark, Sweden and Finland who took part in one of eight studies in these countries. They assessed the participants’ working hours when they joined the studies between 1991 and 2004. Working hours were classified as less than 35 hours a week, 35-40 hours, which was considered as the standard working hours of full-time workers, 41 to 48 hours, 49 to 54 hours, and 55 hours or more a week. None of the participants had atrial fibrillation at the start of the studies.

During the ten-year follow-up period, there were 1061 new cases of atrial fibrillation. This gave an incidence rate of 12.4 per 1000 people in the study, but among the 4,484 people working 55 hours or more, the incidence was 17.6 per 1000. “Those who worked long hours had a 1.4 times higher risk of developing atrial fibrillation, even after we had adjusted for factors that could affect the risk, such as age, sex, socioeconomic status, obesity, leisure time physical activity, smoking and risky alcohol use,” said Prof Kivimaki.

“Nine out of ten of the atrial fibrillation cases occurred in people who were free of pre-existing or concurrent cardiovascular disease. This suggests the increased risk is likely to reflect the effect of long working hours rather than the effect of any pre-existing or concurrent cardiovascular disease, but further research is needed to understand the mechanisms involved.

“A 40% increased extra risk is an important hazard for people who already have a high overall risk of cardiovascular disease due to other risk factors such as older age, male sex, diabetes, high blood pressure, high cholesterol, overweight, smoking and physical inactivity, or living with an established cardiovascular disease. For a healthy, young person, with few if any of these risk factors, the absolute increased risk of atrial fibrillation associated with long working hours is small.”

The study does have some limitations, including the fact that working hours were only assessed once at the beginning of the study and that the type of job (for instance, whether it involved working night shifts) was not recorded.

Source: European Society of Cardiology


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Eating Chocolate, A Little Each Week, May Lower The Risk Of Irregular Heartbeat

There’s delicious news for chocolate lovers: New research suggests the sweet might help keep a common and dangerous form of irregular heartbeat at bay.

The study of more than 55,000 people in Denmark found that those who favored chocolate tended to have a lower risk of atrial fibrillation, an irregular heartbeat that raises stroke risk.

The study tracked people’s health for more than 13 years, over which time more than 3,300 cases of atrial fibrillation emerged.

The study wasn’t designed to prove cause and effect. However, compared with people who ate a 1-ounce serving of chocolate less than once a month, the risk of atrial fibrillation was 10 percent lower among those who ate one to three servings a month, 17 percent lower among those who ate one serving a week, and 20 percent lower among those who ate two to six servings of chocolate a week.

But the benefit then leveled off, with a 16 percent lower risk of atrial fibrillation among adults who ate one or more 1-ounce servings of chocolate a day.

“Our study adds to the accumulating evidence on the health benefits of moderate chocolate intake,” lead author Elizabeth Mostofsky, an instructor in epidemiology at the Harvard School of Public Health, said in a university news release.

Cardiologist Dr. David Friedman said that although study did have its limitations, “it made a sweet suggestion that there is a potential link with higher intake of chocolate consumption and less development of atrial fibrillation events.”

However, he stressed that cardiovascular health relies on more than just chocolate intake. Factors such as regular aerobic exercise and other healthy behaviors “could be a benefit as well,” said Friedman, who is chief of heart failure services at Northwell Health’s Long Island Jewish Valley Stream Hospital in Valley Stream, N.Y.

According to the study authors, prior research has suggested that cocoa and cocoa-containing foods can benefit the heart. That’s because they contain high levels of flavanols, which may improve blood vessel function.

But Mostofsky stressed that “eating excessive amounts of chocolate is not recommended because many chocolate products are high in calories from sugar and fat and could lead to weight gain and other metabolic problems.”

Instead, “moderate intake of chocolate with high cocoa content may be a healthy choice,” she said.

Dr. Rachel Bond helps direct women’s heart health at Lenox Hill Hospital in New York City. Looking at the study data, she noted that “it appears that people who do regularly consume chocolate are also those patients who had less health issues such as diabetes and high blood pressure.

“As these other health issues are known to predispose people to atrial fibrillation, it is hard to say whether eating chocolate was protective or if this population is generally less predisposed to irregular rhythms,” Bond said.

Still, Bond said that in her own practice she is “currently recommending to my chocolate-loving patients the consumption of dark chocolate — in moderation.”

The study was published online in the journal Heart.

Source: HealthDay

Are Blood Thinners Overused in Patients With Irregular Heartbeat?

Steven Reinberg wrote . . . . .

Many people living with the heart rhythm disorder known as atrial fibrillation may be taking unneeded blood thinners, a new study suggests.

These blood thinners, which include aspirin, Plavix and warfarin, are believed to reduce the risk of stroke that can come with atrial fibrillation. But for many atrial fibrillation patients with a low stroke risk, the medications might actually increase both bleeding and stroke risk, researchers reported.

The way most doctors decide whether a patient needs a blood thinner is by using a simple score called CHADS2, which assigns points to patients based on age and other medical risks. A score of 2 is usually needed to recommend a blood thinner, the researchers explained.

But, “people are realizing that the CHADS2 scores are putting too many people above the threshold — it’s pretty easy to get a 2,” explained study author Benjamin Horne, an adjunct assistant professor of biomedical informatics at Intermountain Medical Center Heart Institute in Utah.

For some patients with low CHADS2 scores, the risk of bleeding outweighs the risk of stroke, he added.

“It’s better than flipping a coin, but there are many other scores out there that are more predictive,” Horne said. “The problem with those scores is that it is difficult and time-consuming to use.”

The CHADS2 score breaks down this way: C stands for congestive heart failure, H for high blood pressure, A for age 75 or older, and D for diabetes. S stands for stroke, and the 2 gives an extra point for a previous stroke.

For the study, Horne and his colleagues collected data on nearly 57,000 patients with atrial fibrillation and a CHADS2 score of 0-2. Patients were divided into groups receiving aspirin, Plavix or warfarin or no blood thinner.

At three and five years, the rates of stroke, mini-stroke and major bleeding were higher with any blood thinner, compared with no treatment, the researchers found. The rates of these outcomes were lower among patients taking warfarin than among those taking aspirin or Plavix, the study authors added.

The findings were to be presented Friday at the American College of Cardiology’s annual meeting, in Washington, D.C. Research presented at meetings is considered preliminary until published in a peer-reviewed journal.

Horne said that Intermountain has developed a risk score using a blood test that can help doctors make a more precise decision about a patient’s risk for stroke. When used along with the CHADS2 score, it might prevent low-risk patients from being put on a blood thinner, he said.

But one heart rhythm expert was less certain.

“We have to take this study with caution,” said Dr. Apoor Patel, director of complex ablations in the department of electrophysiology at Northwell Health’s Sandra Atlas Bass Heart Hospital in Manhasset, N.Y.

It’s controversial whether patients with low CHADS2 scores should take blood thinners, Patel said. “It’s something we struggle with every day in clinical practice,” he said.

Stroke risk varies among patients, even those with a CHAD score of just 1, he said.

“I wouldn’t use this one study alone to change practice. When you have a patient with a low CHADS2 score, you have to make a decision about the pros and cons of anticoagulation [blood thinners], and you have to take into account risk factors that aren’t in the score,” Patel said.

Conditions not in the score that can make people more prone to stroke include kidney dysfunction, obesity, smoking and alcohol use, and many others, Patel said.

“When you are faced with a patient with a low CHADS2 score, you have to make a decision patient by patient,” he said. “You have to take into account not just a patient’s score, but a patient’s preferences, as well as risk factors not in the score.”

Source: HealthDay


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New Blood Thinners Reduce Atrial Fibrillation Stroke Risk Without Frequent Monitoring

A new generation of blood thinners can reduce the risk of stroke in patients with atrial fibrillation, without requiring frequent monitoring and dietary restrictions.

But special attention must be given to the patient’s age, kidney function and other factors before prescribing the new medications, according to an article by neurologists at Loyola Medicine and Loyola University Chicago Stritch School of Medicine.

The report by Rochelle Sweis, DO and José Biller, MD, is published in the journal Current Treatment Options in Cardiovascular Medicine.

Atrial fibrillation (AFib) is the most common type of irregular heartbeat, and the prevalence is increasing as the population ages. In AFib, electrical signals that regulate the heartbeat become erratic. Instead of beating regularly, the upper chambers of the heart quiver and blood doesn’t flow well. Blood clots can form, migrate to the brain and cause strokes. AFib is associated with a fivefold increase in the risk of stroke.

Blood thinning medications decrease the stroke risk by approximately 70 percent. For 60 years physicians have prescribed warfarin (Coumadin®) and other blood thinners known as vitamin K antagonists. These medications have been proven to be effective in reducing the risk of blood clots and strokes. But they require continual monitoring and dose adjustments to ensure the drugs thin the blood enough to prevent clots, but not enough to increase the risk of major bleeding. Patients also must restrict their consumption of foods rich in vitamin K, such as spinach, Brussels sprouts, kale, parsley and green tea.

The new blood thinners include dabigatran (Pradaxa®), rivaroxaban (Xarelto®), apixaban (Eliquis®) and edoxaban (Savaysa®). In the right patient population, the new drugs are a safe and effective option for treating atrial fibrillation, Drs. Sweis and Biller write.

Source: EurekAlert!



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