Too Much Salt Might Help Spur Irregular Heartbeat

A high-salt diet could raise your risk for a common heart rhythm disorder, new research suggests.

Atrial fibrillation (A-fib) is a quivering or irregular heartbeat that can lead to blood clots or other complications. It affects millions of people worldwide and puts them at higher risk for stroke and, in rare cases, can lead to heart failure.

This study included 716 middle-aged men and women in Finland who were followed for an average of 19 years. During that time, 74 of the participants were diagnosed with atrial fibrillation.

Those with the highest levels of salt in their diet had a higher rate of atrial fibrillation than those with the lowest salt intake. After accounting for several other risk factors — including age, body fat, blood pressure and smoking — the researchers found that salt consumption was independently associated with the risk of atrial fibrillation.

But the study only found an association — it did not prove that a high-salt diet causes the heart rhythm disorder.

The study was published recently in the Annals of Medicine.

“This study provides the first evidence that dietary salt may increase the risk of new-onset atrial fibrillation, adding to a growing list of dangers from excessive salt consumption on our cardiovascular health,” said study author Tero Paakko, from the University of Oulu in Finland.

“Although further confirmatory studies are needed, our results suggest that people who are at an increased risk of atrial fibrillation may benefit from restricting salt in their diet,” Paakko said in a journal news release.

The chances of developing atrial fibrillation increase with age, and the condition affects about 7 in 100 people 65 and older.

“With estimates suggesting that over three-quarters of salt consumed is already added in processed foods, reducing salt intake at a population level could have a hugely beneficial impact on new-onset atrial fibrillation and overall cardiovascular disease,” Paakko said.

Source: HealthDay


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Neighborhoods with More Green Space May Mean Less Heart Disease

People who live in leafy, green neighborhoods may have a lower risk of developing heart disease and strokes, according to new research published in the Journal of the American Heart Association, the Open Access Journal of the American Heart Association/American Stroke Association.

In this study, the first of its kind, researchers from the University of Louisville investigated the impact of neighborhood greenspaces on individual-level markers of stress and cardiovascular disease risk.

Over five-years, blood and urine samples were collected from 408 people of varying ages, ethnicities and socioeconomic levels, then assessed for biomarkers of blood vessel injury and the risk of having cardiovascular disease. Risk was calculated using biomarkers measured from blood and urine samples. The participants were recruited from the University of Louisville’s outpatient cardiology clinic and were largely at elevated risk for developing cardiovascular diseases.

The density of the greenspaces near the participants’ residences were measured using the Normalized Difference Vegetation Index (NDVI), a tool that indicates levels of vegetation density created from satellite imagery collected by NASA and USGS. Air pollution levels were also assessed using particulate matter from the EPA and roadway exposure measurements.

Researchers found living in areas with more green vegetation was associated with:

  • lower urinary levels of epinephrine, indicating lower levels of stress;
  • lower urinary levels of F2-isoprostane, indicating better health (less oxidative stress);
  • higher capacity to repair blood vessels.

They also found that associations with epinephrine were stronger among women, study participants not taking beta-blockers — which reduce the heart’s workload and lower blood pressure — and people who had not previously had a heart attack.

“Our study shows that living in a neighborhood dense with trees, bushes and other green vegetation may be good for the health of your heart and blood vessels,” said Aruni Bhatnagar, Ph.D., lead study author and professor of medicine and director of the University of Louisville Diabetes and Obesity Center. “Indeed, increasing the amount of vegetation in a neighborhood may be an unrecognized environmental influence on cardiovascular health and a potentially significant public health intervention.”

The findings were independent of age, sex, ethnicity, smoking status, neighborhood deprivation, use of statin medications and roadway exposure.

Previous studies have also suggested that neighborhood greenspaces are associated with positive effects on overall physical and psychosocial health and well-being, as well as reduced rates of death from cardiovascular and respiratory diseases, and improved rates of stroke survival, according to Bhatnagar. However, these reports are largely limited by their reliance on self-reported questionnaires and area-level records and evaluations, said Bhatnagar.

Source: American Heart Association


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Running a Marathon Can Increase Cardiac Strain in Amateur Runners

Full marathons may significantly raise concentrations of several biomarkers of strain on the heart, according to new research in Circulation, Journal of the American Heart Association.

Investigators in Spain compared levels of cardiac biomarkers, including – troponin I and troponin T- in 21 groups of 3 runners each after each individually ran an endurance race of three different lengths – a full marathon, a half marathon and a 10K race. All of the 63 subjects were amateur runners. They also measured levels of biomarkers for cardiac tissue stress.

Although there was little difference in 10-year risk for cardiovascular events between the runners (average about 3 percent), the strain on the heart muscle, as measured by the biomarker levels, was much greater after a full marathon.

The incidence of cardiac arrests in marathoners is only about 1 in 50,000 runners who compete in races, but a high proportion of all exercise-induced cardiac events occur during marathons, especially in men 35 years of age and older.

The number of subjects in the study was not large enough to accurately assess differences in 10-year cardiovascular risk, but the researchers are planning to examine this in a larger group of runners, said lead investigator Juan Del Coso, Ph.D., director of the exercise physiology laboratory at Camilo José Cela University, in Madrid, Spain.

“We typically assume that marathon runners are healthy individuals, without risk factors that might predispose them to a cardiac event during or after a race. But with the growing popularity of long-endurance races, the exponential increase in the number of participants, and the lack of appropriate training in some cohorts of amateur runners, our findings suggest that running shorter endurance races might reduce the strain imposed on the myocardium during running competition,” Del Coso said.

Source: American Heart Association


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Stay Fit to Avoid a Heart Attack

Even if you are a fit and healthy person with no signs of any heart or blood vessel disease, low cardiorespiratory fitness could be a warning sign of future problems, according to a study published in the European Heart Journal [1] today (Thursday).

Cardiorespiratory fitness refers to the ability of the blood circulation and respiratory systems to supply adequate oxygen to muscles during sustained physical activity. The main measure of it is VO2max – the maximum rate of oxygen consumption during exercise that increases with intensity.

In the study published today, 4527 fit and healthy men and women with no history of cardiovascular or lung disease, cancer or raised blood pressure, had their cardiorespiratory fitness assessed when they joined a large, population-based health study in Norway (the HUNT3 study) between 2006-2008. Wearing a face mask and a heart rate monitor, they warmed up for ten minutes on a treadmill before running faster and faster. Their oxygen intake was measured to establish their VO2max. The researchers also gathered information on tobacco use, alcohol consumption, family history of cardiovascular disease, physical activity, weight, height and waist circumference, blood pressure and cholesterol levels.

After an average follow-up time of nearly nine years, the researchers found that greater cardiorespiratory fitness was linked to a lower risk of cardiovascular disease, such as heart attacks. Only 147 participants (3.3%) were diagnosed with heart disease or died from it, or required intervention to unblock clogged arteries during this period.

“We found a strong link between greater fitness and reduced risk of a coronary event during the nine years of follow-up in a very healthy sample of adults,” said Dr Bjarne Nes, a researcher at the Norwegian University of Science and Technology (NTNU). “In fact, the participants who were in the 25% of those with the highest cardiorespiratory fitness had nearly half the risk compared to those in the 25% with the lowest fitness levels.”

The researchers found that, in both men and women, the risk of cardiovascular problems fell by 15% for every extra unit of measurement of cardiorespiratory fitness – metabolic equivalents (METs). METs measure the oxygen required for the energy expended on physical activity, with one MET being the amount needed if a person is sitting quietly (3.5 mL of oxygen per kg of body weight per minute), while high exertion such as running would use about eight METs.

“This indicates that greater cardiorespiratory fitness protects against both chronic and acute heart and blood vessel problems,” said Dr Nes. “Even a small increase in fitness could have a large impact on health.”

The lead author of the study, Dr Jon Magne Letnes, who is a medical doctor and research fellow in the Cardiac Exercise Research Group at NTNU, said: “Our results should encourage the use of exercise as preventive medicine. A few months of regular exercise may be an efficient way of reducing the cardiovascular risk.”

A strength of the study is that cardiorespiratory fitness was measured with a gold-standard maximal exercise test of peak oxygen uptake (VO2peak) – the first to do this in a healthy sample of the general population. Previous studies that have linked fitness to disease risk in healthy populations are mainly based on self-report or less accurate estimates.

A limitation of the study is that participating in voluntary exercise testing introduces the possibility that more active people might choose to join the study, which might reduce its applicability to the general population.

In an accompanying editorial [2], Professor Sanjay Sharma, of St George’s University of London (UK), who is medical director of the London Marathon and chair of the expert cardiology panel for the English Football Association, and Dr Aneil Malhotra, also of St George’s, write: “This study adds to the current literature by demonstrating a similar benefit in an ostensibly healthy population with an incremental benefit that continues beyond 12 METS and suggests that there is no obvious upper threshold for the cardioprotective effects of exercise. Although the number of subjects is laudable, there are several points to note.”

They highlight that there is an unavoidable but inherent selection bias towards participants who were motivated to take part and were probably more aware of lifestyle measures to avoid cardiovascular disease; and the participants were young and healthy, which explains the low number of cardiovascualar-related events during the follow-up period.

They conclude: “In an era where primary prevention is playing an increasingly significant role in society, this study helps highlight that improving CRF [cardiorespiratory fitness] is a pivotal factor in reducing CV [cardiovascular] risk and mortality. Regular physical activity and measures of CRF should be incorporated into clinical practice and CV risk models. All individuals should be encouraged to exercise to the minimal level recommended by the European guidelines for disease prevention, although the observations of Letnes and colleagues and several others suggest that substantially higher physical activity levels and CRF provide additional prognostic benefit. For those who are compromised due to comorbidities or functional status, there is overwhelming evidence that some physical activity is better than none.”

Source: European Society of Cardiology


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Infections May Be a Trigger for Heart Attack, Stroke

Diabetes, high blood pressure and elevated cholesterol are well-known risk factors for cardiovascular disease. But what about just getting sick? Could picking up some type of bug increase your chance of having a stroke or heart attack?

A new study suggests it could.

Researchers have linked infections such as pneumonia and urinary tract infections to an increased risk of having a coronary event, such as a heart attack or stroke, within the next three months.

In the study published recently in the Journal of the American Heart Association, researchers examined a registry of patients tracked over multiple years in four U.S. cities. They looked at 1,312 patients who had a heart attack or other type of coronary event, and 727 other patients who had an ischemic stroke, the kind caused by a blood clot.

Of the heart disease patients, about 37 percent had some type of infection within the previous three months. Among stroke patients, it was nearly 30 percent.

Infections substantially increased the odds of having a heart attack or stroke compared to a year or two earlier in the same group of patients, and those odds were highest in the first two weeks following the infection.

Infections generally trigger an inflammatory reaction in the body, said Dr. Kamakshi Lakshminarayan, a neurologist and senior study author of the research.

The body triggers its white cell production to help ward off an infection, but that process also increases the stickiness of cells called platelets, she said. This encourages the formation of clots that could block the flow of blood to the heart or brain.

“The infection appears to be the trigger for changing the finely tuned balance in the blood and making us more prone to thrombosis, or clot formation,” said Lakshminarayan, an associate professor of epidemiology at the University of Minnesota’s medical school. “It’s a trigger for the blood vessels to get blocked up and puts us at higher risk of serious events like heart attack and stroke.”

The study raises questions about whether patients hospitalized for infections should also begin receiving treatment to protect them from heart disease and stroke. Additional research may provide those answers, Lakshminarayan said.

Urinary tract infection, or UTI, was the most common type of infection reported in the study, followed by pneumonia and other respiratory infections. Skin and blood infections also were reported.

The study included patients treated for infections while hospitalized and those who received outpatient care. Both groups were more likely to have a cardiovascular event within three months of the infection, but this association appeared to be stronger among the inpatient group.

That’s because infections requiring hospitalizations are probably more severe to begin with, said Juan Badimon, a professor of medicine and director of the atherothrombosis research unit at Mount Sinai School of Medicine’s Cardiovascular Institute in New York.

“And if the infection is that severe, we can assume a stronger inflammatory response will result in a higher cardiovascular risk,” said Badimon, who was not involved in the research but co-authored an editorial that accompanied the study.

He described the study’s association between cardiovascular events and all types of infections, not just respiratory ones, a “novel discovery.” But, he said, he would like to have seen researchers dig deeper and note whether the infection source — viral or bacterial — played a role in the increased risk for heart attacks and strokes.

Badimon hopes the findings will encourage the public to make sure their vaccinations are up-to-date, especially during flu season.

Lakshminarayan agreed.

“One of the biggest takeaways is that we have to prevent these infections whenever possible,” she said, “and that means flu shots and pneumonia vaccines, especially for older individuals.”

Source: HealthDay