Wednesday, January 20, 2016

Smoking Thickens Heart Wall,Leading to Heart Failure

 Smoking leads to heart failure by causing thickened heart walls and reducing the heart's ability to pump, a new study shows.

The research also found that smoking more and longer over a lifetime were associated with greater heart damage.
Researchers assessed the hearts of 4,580 U.S. adults using echocardiography -- ultrasound of the heart. The participants' average age was nearly 76. None had any obvious signs of heart disease.
Even after accounting for factors such as age, race, body fat, blood pressure, diabetes and alcohol consumption, current smokers had thicker heart walls and reduced pumping function than nonsmokers and former smokers, the study showed.
The study was published Sept. 13 in the journal Circulation: Cardiovascular Imaging.
It's long been known that smoking is linked with heart failure, even in people without heart disease. But, health experts didn't know how smoking increased the risk of heart failure.
"These data suggest that smoking can independently lead to thickening of the heart and worsening of heart function, which may lead to a higher risk for heart failure, even in people who don't have heart attacks," said study author Dr. Wilson Nadruz Jr. He is a research fellow at Brigham and Women's Hospital in Boston.
These findings reinforce the recommendations stating that smoking is dangerous and should be stopped, Nadruz said in a journal news release.
Study senior author Dr. Scott Solomon is a professor of medicine at Harvard Medical School and Brigham and Women's Hospital. "The good news is that former smokers had similar heart structure and function compared with never-smokers," he said.
"This suggests that the potential effects of tobacco on the [heart wall] might be reversible after smoking cessation," Solomon added.
More information
The American Cancer Society offers a guide to quitting smoking.
SOURCE: Circulation: Cardiovascular Imaging, news release, Sept. 13, 2016

There are already numerous reasons to quit smoking, but a study published this week provides yet another. According to the results, published in the journal Circulation: Cardiovascular Imaging, smoking thickens the heart wall, reducing pumping ability.
[Woman holding a cigarette]
Changes in the heart due to smoking have finally been measured.
Smoking is a major preventable cause of cardiovascular disease.
It has been established that smoking tobacco leads to an increased risk of heart failure, even in individuals without cardiovascular disease.
However, the mechanism by which tobacco damages the heart and causes cardiovascular events has not been found.
Imaging studies examining changes in heart structure associated with smoking have been carried out; however, to date, the results have been conflicting.
Some researchers have found an association with an increase in the mass of the heart's left ventricle; others found no change and others still found a reduction in mass.

The importance of the left ventricle

The left ventricle is of particular interest to tobacco researchers because it is a vital player in the pumping system of the heart. The left ventricle's wall is predominantly made of muscle, so, like any muscle, it increases in size in response to being worked harder.
Certain health factors can increase the heart's workload and, consequently, the thickness of the left ventricle wall (left ventricle hypertrophy); these factors include some heart conditions and high blood pressure.
Left ventricular hypertrophy is known to result in a loss of cardiac function, which can lead to complications that include an interruption to the blood supply of the heart, arrhythmia, and stroke.
In an attempt to produce a clearer picture, a team of researchers recently examined the hearts of thousands of individuals from the Atherosclerosis Risk in Communities (ARIC) Study. They were drawn from four communities in the United States: Forsyth County, NC; Jackson, MS; the suburbs of Minneapolis, MN; and Washington County, MD.
With an average age of 75.5, none had obvious signs of cardiovascular disease. Through questionnaires, the researchers gauged how long each participant had smoked and calculated how many cigarettes they had smoked over their lifetime.
Of the 4,580 individuals, 287 (6.3 percent) were current smokers, 2,316 (50.5 percent) were former smokers, and 1,977 (43.2 percent) had never smoked.
To ensure the results were only charting the interaction between smoking and cardiac events, the investigators accounted for multiple factors within their analysis, including race, age, body mass index, diabetes, blood pressure, and alcohol consumption.

Measuring smoking's impact on the heart

Each participant underwent an echocardiogram - a scan that uses high-frequency sounds to create an image of the heart and nearby blood vessels. When the scans were assessed, it became clear that within the group that smoked, the walls of their left ventricles were significantly thicker.
"These data suggest that smoking can independently lead to thickening of the heart and worsening of heart function, which may lead to a higher risk for heart failure, even in people who don't have heart attacks."
Dr. Wilson Nadruz Jr., Ph.D., lead author
The data showed a clear relationship between the amount of tobacco smoked, the size of the left ventricle wall, and a reduction in pumping function; as Dr. Nadruz says, "the more people smoke, the greater the damage to the heart's structure and function, which reinforces the recommendations stating that smoking is dangerous and should be stopped."
However, the news was not all bad. According to Dr. Scott Solomon, senior study author and professor of medicine at Harvard Medical School and Brigham and Women's Hospital, "former smokers had similar heart structure and function compared with never smokers." In other words, after quitting smoking, the heart seems able to bring itself back within normal, safe parameters.
The study brings to the fore yet another stark message regarding the dangers of smoking tobacco. On the other hand, it gives smokers who are considering quitting another reason to keep trying. It is a difficult habit to kick, but once the cycle has been broken, the heart can heal.
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