Weight Loss May Reverse Course of Atrial Fibrillation

Amy Norton wrote . . . . . . . . . .

Weight loss might help reverse progression of a common heart arrhythmia in obese adults, a new study shows.

Researchers found that when obese adults with atrial fibrillation (a-fib) shed at least 10 percent of their starting weight, most saw the course of their condition reverse. More than half became a-fib-free during the study period.

Experts said the findings underscore the value of sustained weight loss for obese a-fib patients.

“The fact that as little as a 10 percent weight loss resulted in such dramatic change is impressive,” said Dr. Dhanunjaya Lakkireddy, a cardiologist who specializes in treating heart arrhythmias.

“The benefits can be amazing,” he said.

Lakkireddy, who was not involved in the study, is chairman-elect of the American College of Cardiology’s electrophysiology section.

Weight loss is critical, he explained, because obesity feeds many of the factors that contribute to atrial fibrillation — including high blood pressure, diabetes and the nighttime breathing disorder sleep apnea.

“So if you target the root cause,” Lakkireddy said, “you can address these issues in one shot.”

Past research had shown weight loss can ease a-fib symptoms and keep episodes from recurring.

But the new study is the first to show it can also reverse the course of the disease, according to the Australian researchers, led by Melissa Middeldorp of the University of Adelaide.

Atrial fibrillation affects anywhere from 3 million to 6 million Americans, according to the U.S. Centers for Disease Control and Prevention. It arises when the heart’s upper chambers beat erratically instead of maintaining a steady, normal rhythm. Though the problem is not immediately life-threatening, if it persists over time, it can raise the risk of stroke or heart failure.

The new findings, published recently in the journal Europace, are based on 355 obese a-fib patients who were offered a structured weight-loss program.

It included individualized diet and lifestyle advice. But in general, patients cut down on calories and processed, high-carbohydrate foods. They also started exercising: First, they took on low-intensity activity three or four times a week, then built toward sessions of moderate exercise, such as brisk walking. The goal was 200 minutes per week, or about 30 minutes each day.

They also received help with managing all their a-fib risk factors such as monitoring their blood pressure, getting their blood sugar levels down, and treating sleep apnea.

Four years later, the study found, people who’d managed to lose at least 10 percent of their weight were faring best.

Overall, 135 people lost that much weight. And 88 percent of them had been either free of a-fib in the past year, or had gone from persistent a-fib episodes to “paroxysmal” a-fib.

Persistent a-fib episodes last for at least a week, or even months. They may require treatment — with either drugs or an electrical “shock” to the heart — to end them.

In contrast, paroxysmal episodes last less than a week and go away on their own.

The picture was different for patients who lost little weight. Of the 116 who lost less than 3 percent of their weight, 41 percent progressed from paroxysmal a-fib to persistent. Only one patient improved from persistent to paroxysmal a-fib.

“Progression of the disease is shown to have a direct link with the degree of weight loss,” Middeldorp said in a statement. “Without weight loss, there is a progression of AF [a-fib] to more persistent forms of AF.”

Doctors already encourage obese a-fib patients to lose weight, according to Lakkireddy. But, he noted, it is notoriously difficult to keep excess pounds off.

The patients in this study went through a fairly intensive formal weight-loss program — and that may be what it takes. Lakkireddy said a-fib patients who need to lose weight can start by asking their doctor for resources to help them.

“Don’t be lured by these fad diets,” he cautioned. Certain diets could be dangerous for people with a-fib. Imbalances in nutrients like potassium and magnesium can spur heart rhythm disturbances.

Instead, Lakkireddy said, go for healthy, sustainable changes.

“In general,” he said, “people will benefit from reducing portion sizes, cutting out sugar and eating more vegetables and lean protein.”

Source: HealthDay


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Depression Linked to Common Heart Rhythm Disorder

Depression may increase the risk for atrial fibrillation, the most common heart rhythm disorder that can lead to blood clot formation and stroke, according to preliminary research presented at the American Heart Association’s Epidemiology and Prevention | Lifestyle and Cardiometabolic Health Scientific Sessions 2018, a premier global exchange of the latest advances in population based cardiovascular science for researchers and clinicians.

Participants in the study who scored highest on a clinical screening test for depression as well as those taking anti-depressant medication had more than a 30 percent higher risk for developing atrial fibrillation than people with normal test scores and those not taking medications for depression.

The results suggest an association between two very common disorders, a finding that demands further research and greater awareness among both clinicians and patients, researchers said.

“Our findings identify a large portion of Americans who may be at an increased risk for developing atrial fibrillation and who may benefit from more targeted efforts to prevent this arrhythmia,” said study lead investigator Parveen Garg, M.D., M.P.H, assistant professor of clinical medicine at the Keck School of Medicine of the University of Southern California in Los Angeles. “If our findings are affirmed in future studies, especially those that formally assess for clinical depression, then we will need to see if treating depression may, in fact, lower the risk for atrial fibrillation.”

The findings stem from the national Multi-Ethnic Study of Atherosclerosis (MESA) study, which involved more than 6,600 people from various ethnic groups. Participants, average age 62, had no known heart disease at the onset of the study and were followed for a median of 13 years.

Exactly how depression disrupts heart function remains unclear, researchers said, but several possible mechanisms have been suggested. These include increased levels of inflammation as well as elevated levels of certain hormones that directly or indirectly interfere with the heart’s ability to stay in a normal rhythm.

The new findings add further credence to the notion that mental health and heart health are closely intertwined, underscoring previous research showing an association between depression and heart disease.

“Clinicians and patients should be aware that depression has been shown in several studies to be a risk factor for heart disease in general and, in this study, for atrial fibrillation as well,” Garg said. “Treating depression is important for many reasons including cardiovascular health.”

Atrial fibrillation occurs when the upper two chambers of the heart begin to quiver chaotically, compromising their ability to propel blood into the two lower chambers of the heart. When blood pools in the upper chambers, it can lead to clot formation, which in turn can cause a stroke. Untreated atrial fibrillation doubles the risk of heart-related deaths and is associated with a 5-fold increased risk for stroke.

More than 16 million adults in the United States suffer from depression, according to estimates from the National Institutes of Health. Atrial fibrillation, the most common heart-rhythm disorder, affects some 2.7 million Americans, according to the American Heart Association’s 2018 Heart and Stroke Statistical Update.

Source: American Heart Association


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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


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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


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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


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