Test Measures Very Low Levels of Heart Protein, Troponin I
By Salynn Boyles
WebMD Health News
Reviewed by Louise Chang, MD
Dec. 27, 2011 -- When someone is having chest pain or other heart symptoms, it's not always easy to tell whether they've suffered a heart attack.
An electrocardiogram (ECG), one of the key tests used to confirm heart damage, isn't always conclusive. When that happens, doctors may use a blood test that measures a muscle protein in the blood. If someone has high levels of the protein, known as troponin I, they are more likely to have suffered heart damage.
Now, an even more sensitive version of the test may be more helpful in ruling out a heart attack accurately and quickly, according to new research in the Journal of the American Medical Association.
Researchers from Germany's University Heart Center Hamburg who used the newly developed test were able to accurately rule out a heart attack close to 99% of the time by repeating the test.
Among the 1,818 patients in the study, the more sensitive test proved to be more effective for ruling out heart attacks than regular troponin I testing.
"This test appears to be able to detect more subtle forms of damage to the heart," says American Heart Association president Gordon Tomaselli, MD, who is chief of cardiology at Johns Hopkins Heart and Vascular Institute in Baltimore.
Over-diagnosis of heart attacks is a common issue that can lead patients to get treatments that may not be needed.
Both highly sensitive troponin I and the conventional version of the blood test were found to be better than the other biomarkers for confirming or ruling out heart attacks.
For the most accurate result, the test was repeated within three hours after hospital admission.
Tomaselli tells WebMD that more research is needed to validate the findings. Highly sensitive versions of the test may be so sensitive that they over-diagnose heart attacks since very low blood concentrations of the protein can be found in people not having a heart attack.
He adds that if the findings are validated, highly sensitive troponin I tests are likely to be widely used in the emergency setting.
"This test has not completely overcome the problem (of over-diagnosis), but it is very effective at ruling out heart attacks with serial testing," he says.
SOURCES: Keller, T. Journal of the American Medical Association, Dec. 28, 2011.Gordon Tomaselli, MD, chief of cardiology, Johns Hopkins Heart and Vascular Institute, Baltimore.News release, JAMA Media.
©2011 WebMD, LLC. All Rights Reserved.
TUESDAY, Dec. 20 -- People suffering from high blood pressure, or hypertension, who keep their blood pressure levels under control may add years to their life, a new study suggests.
In fact, those in the study who took medicine to lower their blood pressure for more than four years reduced their risk of dying from cardiovascular disease over a 20-year period, the researchers found.
"For the first time, we prove that treating high blood pressure prolongs life," said lead researcher Dr. John Kostis, a professor of medicine & pharmacology at UMDNJ-Robert Wood Johnson Medical School in New Brunswick, N.J.
"If you take your medications for a month, you live an extra day," he said. "One day benefit from a month of treatment sounds small, but if you start treatment at 40, for example, then you live a couple of extra years."
Although the antihypertensive diuretic chlorthalidone was used in the study, it really doesn't make a difference which antihypertensive one uses; the benefit in terms of life expectancy should be the same, Kostis said.
"The main thing is to take medication to get blood pressure under control," he said. "Treat your hypertension early so you can benefit from a longer, happier life."
The report was published in the Dec. 21 issue of the Journal of the American Medical Association.
To determine the effect antihypertensive drugs might have on extending life, Kostis and his colleagues used data from the Systolic Hypertension in the Elderly Program (SHEP) trial.
In that trial, conducted between 1985 and 1990, more than 4,000 hypertensive patients were randomly assigned to take chlorthalidone or an inactive placebo. The patients in the study were an average of 72 years of age.
Kostis noted that if chlorthalidone didn't work, patients were given a beta blocker.
At the end of the trial, all of the patients were advised to get their hypertension treated, the researchers noted.
When Kostis' group looked at the 22-year follow-up data in 2006, about 60 percent of the participants had died. Of these, 59.9 percent of those taking chlorthalidone had died as did 60.5 percent of those who received placebo.
The researchers found that life expectancy and survival were longer for those who received chlorthalidone during the trial compared with those given a placebo.
The gain in life expectancy, for death from any cause, linked to treating hypertension was about half a day per month of treatment, they found.
Also, people taking an antihypertensive gained about one day free from cardiovascular death per month of treatment, and had less of a chance of dying from cardiovascular disease than those who had received placebo; 28 percent versus 31 percent, respectively.
Dr. Gregg C. Fonarow, a professor of cardiovascular medicine and science at the University of California, Los Angeles, said that "hypertension is a major modifiable risk factor for heart attacks, strokes, heart failure, renal failure and premature cardiovascular death."
Treatment of adults with elevated blood pressure with antihypertensive medications has been shown in many trials to significantly reduce the risk of fatal and nonfatal cardiovascular events, heart failure and renal failure, he said.
"However, as most trials were three to five years in duration, whether there are long-lasting effects on life expectancy from treating hypertension has not been well-studied," Fonarow said.
This study provides further compelling evidence of the enduring benefits of treating hypertension, Fonarow said.
"With over half of the 76 million men and women in the United States who have hypertension not having their blood pressure well-controlled, improved detection, treatment and control of hypertension is imperative," he added.
SOURCES: John B. Kostis, M.D., professor, medicine & pharmacology, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, N.J.; Gregg C. Fonarow, M.D., The Eliot Corday Professor of Cardiovascular Medicine and Science, University of California, Los Angeles; Dec. 21, 2011, Journal of the American Medical Association
TUESDAY, Dec. 20 -- Precautionary measures need to be used in conjunction with screening to protect all college athletes from sudden death related to overexertion and exhaustion, researchers say.
After a college football player died from complications due to sickle cell trait during a workout, the NCAA implemented mandatory screening of all Division I student athletes.
University of Michigan researchers evaluated the effect of the policy and concluded that screening tests alone would help identify more than 2,000 athletes with sickle cell trait, but they added that screening alone is not enough.
Having sickle cell trait, which occurs primarily in African Americans, means carrying one gene for sickle cell disease, rather than having the condition. However, carrying the trait alone has previously been found to increase the risk of sudden death. Dehydration and exercising in intense heat can increase the risk for carriers.
"Although the policy is well-intentioned, screening is just the first step," lead author Dr. Beth Tarini, an assistant professor in the pediatrics and communicable diseases department, said in a university news release. "In addition to educating athletes and staff, precautionary measures need to be strictly enforced," she added.
"The culture in sports to push ourselves dangerously beyond our limits is powerful," Tarini said. "Implementing policies to identify those at risk provides a false sense of security if we aren't diligent about monitoring and protecting the health and safety of our student athletes."
Without a strictly enforced universal intervention policy, about seven NCAA Division I athletes would die suddenly as a complication of sickle cell trait over a 10-year period, the researchers concluded.
"In the end, enforcing safe training measures to protect all NCAA student-athletes -- not just those in Division I -- from sudden death related to [sickle cell trait] will benefit all athletes," Tarini said. "That's a win-win situation from a policy perspective."
The study was released online in advance of publication in an upcoming print edition of the journal Health Services Research.
-- Robert Preidt
SOURCE: University of Michigan Health System, news release, Dec. 9, 2011
Study Suggests Regularly Checking Pulse to See Where You Stand
By Denise Mann
WebMD Health News
Reviewed by Laura J. Martin, MD
Dec. 20, 2011 -- Your resting heart rate or pulse may provide important clues about your current and future heart health.
It has been known that a high resting heart rate is a risk for heart disease. Now new research suggests that an increase in resting heart rate over time may actually place a person at greater risk for dying from heart disease and/or other causes in the future. The findings appear in the Dec. 21 issue of the Journal of the American Medical Association.
For adults, a normal resting heart rate is usually between 60 to 100 beats per minute. Athletes tend to have lower resting heart rates.
"A healthy adult is expected to have about 70 beats per minute in resting heart rate and the point is to follow it over time -- if it increases more than 10 beats you may talk to your family doctor to get advice about lifestyle changes and/or get a thorough check of your [heart and blood vessel] system," study author Ulrik Wisloff, PhD, tells WebMD in an email.
Curious as to where you stand?
When you wake in the morning, find your pulse on your wrist or neck. Choose the spot that works best for you. Make sure there is a clock nearby. After you find the beat, count how many beats occur within one minute.
The study included nearly 30,000 men and women without known heart disease. Researchers measured their resting heart rate twice about 10 years apart. Compared to healthy people whose resting heart rate stayed less than 70 beats per minute during a 10-year period, those whose pulse was less than 70 beats per minute at the first measurement and then greater than 85 at the second were more likely to die from heart disease and other causes after 12 years of follow-up.
Participants whose heart rate was between 70 and 85 at the first measure and then greater than 85 the next time it was measured were also more likely to die from heart disease or other causes.
Further study is needed, but the findings may help identify a group of seemingly healthy people who are at risk for heart disease before they develop any other signs or symptoms, the study authors conclude.
Robert J. Myerburg, MD, is a professor at the University of Miami Miller School of Medicine who for 31 years served as chief of the school's division of cardiology. "We have known for a long time that a higher heart rate is associated with increased risk for heart disease," he says.
The people in the new study were healthy, he points out. The new study findings may not apply to people with heart disease.
Don't panic about these findings, says Kousik Krishnan, MD. He is director of the Arrhythmia Device Clinic at Rush University Medical Center in Chicago. "People who have a heart rate that goes up over time may have some other underlying condition," he says. "If you have a resting heart rate that is over 100, ask your doctor to do a physical exam to see if something else is going on."
Suzanne Steinbaum, DO, says the study provides empowering information. She is a preventive cardiologist at Lenox Hill Hospital in New York City. "Resting heart rate gives us an indication about our heart health," she says. "The best way to keep your resting heart rate down is aerobic exercise."
This means that if your resting heart rate is edging up, your activity level has probably taken a dive. "You are still in control," she says. "Start exercising more and see a doctor to make sure something else isn't going on."
SOURCES: Robert J. Myerburg, MD, professor of medicine and physiology, University of Miami Miller School of Medicine, Miami.Kousik Krishnan, director, Arrhythmia Device Clinic, Rush University Medical Center, Chicago.Suzanne Steinbaum, DO, preventive cardiologist, Lenox Hill Hospital, New York City.Nauman, J. Journal of the American Medical Association, 2011.Ulrik Wisloff, PhD, K.G. Jebsen Center of Exercise in Medicine, departments of circulation and medical imaging, Trondheim, Norway.
©2011 WebMD, LLC. All Rights Reserved.
MONDAY, Dec. 19 -- Snipping certain nerves may help prevent dangerous heart rhythms caused by stress, a small, new study suggests.
An adrenalin-driven "fight or flight" stress reaction in response to danger is normal, but this reaction is abnormally strong in some people and can lead to excessive sweaty palms ( hyperhidrosis) and irregular heart rhythms called ventricular arrhythmias, which originate in the lower chambers of the heart.
Now, a team of cardiologists at the University of California, Los Angeles has found that snipping nerves related to the sympathetic nervous system on both the right and left sides of the chest may help prevent these ventricular arrhythmias, also referred to as "electrical storms."
Ventricular arrhythmia kills 400,000 people in the United States each year and is a leading cause of death in the nation, according to a UCLA Health Sciences news release. Treatments include medications, an implantable cardioverter defibrillator and a procedure called catheter ablation, which provides a targeted burn to the tiny area of the heart that causes the irregular heartbeat.
"When these treatment options fail, especially for a patient experiencing a life-threatening electrical storm, the situation becomes critical. We are always seeking additional options to help patients," senior study author Dr. Kalyanam Shivkumar, director of the UCLA Cardiac Arrhythmia Center and co-director of the Oppenheimer Family Center for Neurobiology of Stress at UCLA, said in the news release.
The new procedure, called a bilateral cardiac sympathetic denervation, was performed on six patients. After the surgery, four of the patients had a complete response and no longer experienced arrhythmias, one patient had a partial response, and one had no response.
One cardiologist said the nerve snip may have a place in caring for arrhythmias.
"Autonomic influences on the cardiac rhythm may be very potent and their subsequent manipulation to aid in rhythm management have been utilized for several years," said Dr. Larry Chinitz, director of the Heart Rhythm Center at NYU Langone Medical Center in New York City. He called the new procedure "an innovative use of this surgical technique and one that may prove to be a potent adjunct to currently available therapies."
The study, which was funded by the U.S. National Institutes of Health, appears in the Dec. 27/Jan.3 issue of the Journal of the American College of Cardiology.
-- Robert Preidt
SOURCES: Larry Chinitz, M.D., director, Heart Rhythm Center, NYU Langone Medical Center, New York City; University of California, Los Angeles, Health Sciences, news release, Dec. 19, 2011
FRIDAY, Dec. 16 -- Playing football may put certain teens at increased risk for stroke, according to a small new study.
Researchers from the Indiana University School of Medicine in Indianapolis analyzed three case studies of teen football players who suffered a stroke, and identified some factors that could boost the likelihood of a stroke.
These factors included: an increase in hyperventilation, repeated brain injury, use of anabolic steroids, use of highly caffeinated energy drinks and obesity.
Obesity is linked to a twofold risk because it increases the force of impacts between players and also heightens the risk for other stroke risk factors such as high blood pressure (hypertension), according to researchers Dr. Jared Brosch and Dr. Meredith Golomb.
"Two of our subjects had mild hypertension, but were too young to have had the many years of exposure that would lead to chronic vascular injury," they said in a journal news release.
The study recently appeared online in the Journal of Child Neurology.
"Organized childhood tackle football in the United States can begin at age 5 years, leading to potentially decades of repeated brain injuries. In addition, the body mass index of the United States pediatric football-playing population continues to increase, so the forces experienced by tackled pediatric players continues to increase," the researchers wrote.
"Further work is needed to understand how repeated high-impact large-force trauma from childhood football affects the immature central nervous system," they concluded.
-- Robert Preidt
SOURCE: Journal of Child Neurology, news release, Dec. 8, 2011