Blood Thinners May Also Protect Brains of A-Fib Patients

Blood thinners may pull double duty for people with the heart rhythm disorder atrial fibrillation: New research suggests they help prevent dementia as well as stroke.

Because atrial fibrillation increases the risk for stroke, people with the condition are often prescribed blood thinners (also known as anticoagulants) to prevent blood clots that can cause a stroke.

Atrial fibrillation also increases the risk for dementia. During the study, more than 26,000 of the 440,000 participants, all with atrial fibrillation, were diagnosed with dementia.

At the time they joined the study, about half of the participants were taking oral anticoagulants, such as warfarin, Eliquis (apixaban), Pradaxa (dabigatran), Savaysa (edoxaban) or Xarelto (rivaroxaban).

The researchers found that people taking anticoagulants were 29 percent less likely to develop dementia than were those who were not taking the blood thinners.

When the researchers focused on people who continued to take the drugs, they found an even larger reduction (48 percent) in the risk for dementia. They also found that the sooner people started taking blood thinners after their diagnosis of atrial fibrillation, the lower their risk for dementia.

Along with not taking blood thinners, the strongest predictors for dementia were age, Parkinson’s disease and alcohol abuse, according to the study, published Oct. 25 in the European Heart Journal.

The findings strongly suggest that blood thinners reduce the risk for dementia in people with atrial fibrillation, but proving that would not be possible, the Swedish researchers said.

“In order to prove this assumption, randomized placebo-controlled trials would be needed, but such studies cannot be done because of ethical reasons,” researchers Leif Friberg and Marten Rosenqvist, of the Karolinska Institute in Stockholm, said in a journal news release. “It is not possible to give placebo to [atrial fibrillation] patients and then wait for dementia or stroke to occur.”

However, the findings show that people with atrial fibrillation should start taking blood thinners as soon as possible after their diagnosis and continue to take the drugs, Friberg noted.

“Patients start on oral anticoagulation for stroke prevention but they stop after a few years at an alarmingly high rate,” he said. “In the first year, approximately 15 percent stop taking the drugs, then approximately 10 percent each year.”

“If you know that [atrial fibrillation] eats away your brain at a slow but steady pace and that you can prevent it by staying on treatment, I think most patients would find this a very strong argument for continuing treatment,” he said.

Source: HealthDay


Today’s Comic

Advertisements

Irregular Heartbeat Linked to Higher Thyroid Hormone Levels

Individuals with higher levels of thyroid hormone (free thyroxine, FT4) circulating in the blood were more likely than individuals with lower levels to develop irregular heartbeat, or atrial fibrillation, even when the levels were within normal range, according to new research in the American Heart Association’s journal Circulation.

“Our findings suggest that levels of the thyroid hormone, free thyroxine, circulating in the blood might be an additional risk factor for atrial fibrillation,” said study lead author Christine Baumgartner, M.D., specialist in General Internal Medicine from the University Hospital of Bern, Switzerland, and currently a postdoctoral scholar at University of California San Francisco. “Free thyroxine hormone levels might help to identify individuals at higher risk.”

In the United States, irregular heartbeat (atrial fibrillation) affects between 2.7 to 6.1 million people and is estimated to affect up to 12.1 million people by 2030. It occurs when the two upper chambers of the heart, called the atria, beat irregularly and faster than normal. Symptoms may include heart palpitations, dizziness, sweating, chest pain, anxiety, fatigue during exertion and fainting, but sometimes patients with atrial fibrillation have no symptoms at all. Although people can live with irregular heartbeat, it can cause chronic fatigue and increase the risk of serious illnesses, such as stroke and heart failure, potentially associated with lifelong disability and even death. Fortunately, medication and other therapies are available to treat irregular heartbeat and reduce the risk of the associated symptoms and complications.

The thyroid gland is a small gland in the neck. In response to thyroid-stimulating hormone released by the pituitary gland, the thyroid gland secretes thyroid hormones required to regulate energy metabolism. Patients with low levels of thyroid hormone, or hypothyroidism, may require medications containing thyroid hormone (thyroxine) to increase their hormonal levels. Sometimes intake of thyroxine sometimes can increase these levels too much.

Previous studies showed that the risk of irregular heartbeat is greater among individuals who produce too much thyroid hormone than among those with normal hormonal levels. What was unclear, however, was whether levels that were high but still within the normal range could also increase the risk of irregular heartbeat.

To understand this relationship, investigators looked at the occurrence of irregular heartbeat among individuals with thyroid hormone levels that were still within normal range. They found that individuals with higher blood levels of FT4 within the normal range at the beginning of the study were significantly more likely than those with lower levels to subsequently develop irregular heartbeat.

When separated into four equal-sized groups, the group with the highest FT4 levels had a 45 percent increased risk of irregular heartbeat, compared to the group with the lowest levels. Even more modest increases in thyroid hormone were associated with an increased risk. Among individuals with the second highest levels, the risk was 17 percent greater, and among those with the third highest levels the risk was 25 percent greater, compared to those with the lowest levels. High levels of thyroid-stimulating hormone (TSH) within the normal range, however, were not associated with an increased risk of atrial fibrillation.

“Patients who are treated with thyroxine, one of the most frequently prescribed drugs in the United States, generally have higher circulating free thyroxine levels compared to untreated individuals,” Baumgartner said. “So, an important next step is to see whether our results also apply to these patients, in order to assess whether target free thyroxine thyroid hormone concentrations for thyroid-replacement therapy need to be modified.”

The investigators analyzed data from 11 studies from Europe, Australia, and the United States that measured thyroid function and the occurrence of irregular heartbeat. Overall, the studies included 30,085 individuals. Their average age was 69 years, and slightly more than half were women. On average, follow-up ranged from 1.3 to 17 years. The investigators obtained the studies by searching the MEDLINE and EMBASE medical databases through July 2016.

Source: American Heart Association


Today’s Comic

Men Develop Irregular Heartbeat Earlier Than Women; Extra Weight a Factor

Men develop a type of irregular heartbeat, known as atrial fibrillation, about a decade earlier than women on average, and being overweight is a major risk factor, according to a large new study published in the American Heart Association’s journal Circulation.

In atrial fibrillation, the upper chambers of the heart, or atria, quiver instead of beat to move blood effectively. Untreated atrial fibrillation increases the risk of heart-related death and is linked to a five times increased risk of stroke. In the new research, having the condition more than tripled a person’s risk of dying.

“It’s crucial to better understand modifiable risk factors of atrial fibrillation,” said study author Christina Magnussen, M.D., a medical specialist in Internal Medicine and Cardiology at the University Heart Center in Hamburg, Germany. “If prevention strategies succeed in targeting these risk factors, we expect a noticeable decline in new-onset atrial fibrillation.”

This would lead to less illness, fewer deaths and lower health-related costs, she said.

Researchers reviewed records of 79,793 people (aged 24 to 97) in four community-based studies in Europe. The participants did not have atrial fibrillation at the outset. Later assessments of their health — with a median follow-up period of 12.6 to a maximum of 28.2 years — showed that 4.4 percent of the women and 6.4 percent of the men had been diagnosed with the condition.

Researchers noted atrial fibrillation:

  • diagnosis rates jumped when men were 50 or older and women were 60 or older;
  • developed in about 24 percent of both men and women by age 90;
  • onset was tied to higher blood levels of C-reactive protein (inflammation marker) in men; and
  • new atrial fibrillation cases increased more in men than women with increases in body mass index (BMI): 31 percent in men and 18 percent in women.

“We advise weight reduction for both men and women,” Magnussen said. “As elevated body mass index seems to be more detrimental for men, weight control seems to be essential, particularly in overweight and obese men.”

Researchers were surprised to find that higher total cholesterol, a risk factor for heart disease, lowered risk for developing atrial fibrillation, especially in women, although exactly why is not clear.

Due to its design, the study could not shed light on pathophysiological factors causing sex differences in atrial fibrillation risk. The authors also note that atrial fibrillation might have been underdiagnosed at the study’s start and later records may not reflect all cases. Strengths of the research include that it studied the condition in the general population and noted how individuals fared over long periods.

Since study participants were from both northern and southern Europe, the findings will probably apply to other Caucasian populations but cannot be generalized to other groups, Magnussen said. However, since BMI in the study was such a strong risk factor for atrial fibrillation, it is likely to also be impactful in other groups, she added.

According to American Heart Association statistics, between 2.7 and 6 million Americans are living with atrial fibrillation, and more than 12 million are expected to have the condition in 2030. Risk factors include body mass index, systolic blood pressure, total cholesterol, diabetes, smoking, alcohol consumption, previous heart attack or stroke and presence of heart disease.

Source: American Heart Association


Today’s Comic

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


Today’s Comic