FRIDAY, March 21 (HealthDay News) -- In dogs with damaged hearts, implanted pacemakers triggered fast improvements in tissue levels and the activity of a number of proteins crucial to heart health, says a Johns Hopkins study.

The researchers said their findings are believed to be the first detailed chemical analysis of the biological effects a pacemaker has on the heart. This new information could lead to improvements in the use of combined pacemaker/drug treatments for congestive heart failure patients.

"We are learning that pacemaker therapy does profoundly more than just mechanically correct how the heart beats; in fact, it produces major chemical changes that benefit the muscle," lead investigator Khalid Chakir, a postdoctoral cardiology research fellow at Hopkins, said in a prepared statement.

In this study, Chakir and colleagues induced "wobbly, discoordinated contraction" in the hearts of 22 dogs. In half the dogs, this asymmetric heart failure was allowed to take its natural course. The other dogs received a cardiac pacemaker.

Tissue analysis found major changes in the production or activity levels of 17 proteins known to be involved with heart cell stress, survival and death. These changes were especially notable in the dogs that didn't have their hearts "retuned" by a pacemaker.

In the dogs that did receive a pacemaker, the tissue levels and activity of these proteins were restored toward normal. The findings were published online in Circulation.

"Our results really help explain how pacemakers act much like a drug, actually changing the biology of the heart, and also explain why people can feel so much better after just two to six months with the device," study senior investigator Dr. David Kass, a cardiologist and professor at the Johns Hopkins University School of Medicine and its Heart Institute, said in a prepared statement.

Each year in the United States, more than a million people are diagnosed with congestive heart failure, in which the heart weakens and isn't able to pump enough blood to the rest of the body. About 25 percent of congestive heart failure patients suffer from non-uniform heart contraction, which requires implantation of a pacemaker to restore normal heartbeat, according to background information in a news release about the study.

Pacemakers can help extend people's lives for month or years or help them return to normal daily activities. It had been believed that pacemakers simply provided a mechanical solution for heartbeat malfunction.

"Now that we have found that resynchronization is doing more fundamental things to the heart muscle, we should be able to better combine these devices with drugs to maximize long-term survival and outcomes," Kass said.

More information

The U.S. Food and Drug Administration has more about cardiac pacemakers.

WEDNESDAY, March 19 (HealthDay News) -- A combination of cholesterol-associated gene variants can increase a person's risk for heart attack, stroke or sudden cardiac death, Massachusetts General Hospital researchers report.

It may someday be possible to test for these gene variants in order to identify patients who may require more intense monitoring and might benefit from earlier use of cholesterol-lowering medications and other measures to reduce their increased risk for cardiovascular events, the researchers said.

"We feel that our data provides two insights," study lead author Dr. Sekar Kathiresan, director of preventive cardiology at MGH, said in a prepared statement. "First, we provide a foundation for the possibility that a panel of gene variants will eventually be useful in preventive cardiac care. Second, we show that the combination of multiple variants related to cholesterol importantly contribute to the genetic risk for heart attack."

In analysis of data from 5,414 Swedish adults, Kathiresan and colleagues focused on a combination of 9 single-nucleotide polymorphisms (SNPs) previously associated with cholesterol levels. The researchers also looked at the participants' high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol levels, and their subsequent medical histories.

The participants were given a genotype score, ranged from 0 to 18, based on how many copies of the unfavorable SNPs they had. Those with higher genotype scores had higher LDL (bad) cholesterol and lower HDL (good) cholesterol levels. Those with genotype scores of 11 or higher had a 63 percent greater risk of a cardiovascular event than those with score of nine or lower.

In the overall study population, testing for the panel of nine SNPs was no better than standard risk factors for predicting risk of cardiac events. However, among those classified at intermediate risk by standard measures, the results of testing for the panel of nine SNPs significantly improved the ability to identify people with truly elevated or reduced cardiac event risk levels, the researchers said.

The study appears in the March 20 issue of the New England Journal of Medicine.

"A current clinical dilemma is how early to start patients on cholesterol-lowering medications like statins that can reduce the risk of heart attack," Kathiresan said. "Our data suggest those individuals classified as higher risk based on a genetic test may deserve more intense pharmacological and lifestyle treatments."

However, before this approach can actually be used to help patients, he added, "we need to discover all the risk-related variants -- and there will probably be 50 to 100 -- and then conduct clinical studies confirming that this information can reliably guide patient care."

More information

The U.S. Centers for Disease Control and Prevention has more about heart disease risk factors.

THURSDAY, March 13 (HealthDay News) -- Secondhand smoke causes signs of cardiovascular damage in children, especially the very youngest, new research contends.

The findings, which focused on children from 2 to 14 years old, showed that environmental tobacco exposure (second-hand smoke) caused increased markers of inflammation and signs of vascular injury, suggesting an increased risk of heart disease. The youngest children appeared to be more affected than teens.

"Toddlers are smokers by default," said one of the study's authors, John Bauer, director of the Center for Cardiovascular Medicine at Nationwide Children's Hospital and Research Institute in Columbus, Ohio. "Forty percent of toddlers in our study had nicotine content that in adults would suggest that they were active smokers. But, an active smoker has a filter on cigarettes. The toxicity from smoke that is inhaled in the atmosphere is worse because there's no filter."

Results of the study were to be presented Thursday at the American Heart Association's Cardiovascular Disease Epidemiology and Prevention meeting, in Colorado Springs.

Bauer and his colleagues took hair and blood samples from 125 children. Fifty-seven were between the ages of 2 and 5; 68 were between 9 and 14. Hair samples were used to measure nicotine exposure, and blood samples were used to look for a type of cell called an endothelial progenitor cell (EPC). These cells replenish the endothelium (the lining of the blood vessels) and provide clues to levels of cardiovascular health.

The researchers also asked the parents how many smokers children had been exposed to in a 24-hour period.

Children in the youngest age group had almost six times the average nicotine levels than older children did. Toddlers had an average nicotine level of 12.68 nanograms per milligram of hair, while older kids had an average level of 2.57 nanograms per milligram.

"Toddlers were more exposed," Bauer said. "Toddlers are like fish in a fish bowl. They're strapped pretty closely to their parental units, which exposes them to more smoke than adolescents who live in the same set of circumstances."

"Toddlers also breathe more rapidly, so they inhale more," added one of Bauer's co-authors, Dr. Judith Groner, a pediatrician and ambulatory care physician at Nationwide.

The youngest children also had higher levels of an inflammatory marker called soluble intracellular adhesion molecules, and there was an inverse relationship between EPC levels and exposure to smoke in both age groups, though again, the effect of secondhand smoke was more pronounced in the younger children.

These findings are similar to what has been found in adult smokers, according to the study authors. EPC levels haven't yet been studied in adults exposed to secondhand smoke.

"Based on markers of vascular stress, toddlers are hit harder," said Bauer. "To what extent this is reversible if exposure is stopped isn't known. In adults, there is evidence that when active smokers quit smoking that the risk of heart disease is lower, but some research suggests that cardiovascular disease may be imprinted in early life, so we don't know if this is reversible or not."

"This study suggests that if you have a toddler, make sure they're out of harm's way," he added.

Dr. Devang Doshi, director of pediatric pulmonology, allergy and immunology at Beaumont Hospital in Royal Oak, Mich., said, "This study gives us more insight into the bad effects of secondhand smoke exposure from a respiratory and cardiac standpoint."

"A lot of people don't realize that when you smoke in the house, children are continuously exposed. It's always in the house; the smoke doesn't just go away," he added.

Doshi said his first advice to parents is to quit smoking. Failing that, he said he advises parents to go outside, away from the house to smoke, and to wear at least two layers of clothing. Then, when they come back in the house, he recommends removing the top layer of clothing and washing your hands to try to limit your child's exposure.

"Don't smoke," advised Groner, "and have a total ban on smoking around your child."

More information

To learn more about the effects of secondhand smoke, visit the American Lung Association  .

FRIDAY, Feb. 22 (HealthDay News) -- Several new studies point to the promise of new ways to treat different types of stroke.

The research was presented during a teleconference Friday at the American Stroke Association's International Stroke Conference in New Orleans.

The first trial found some benefit when tPA, the only approved therapy for acute ischemic stroke, was given outside the usual three-hour treatment window. Patients in this Australian trial who were given tPA three to six hours after having a stroke had increased restoration of blood flow and a smaller area of the brain was deprived of blood. The study was expected to be published in the April issue of The Lancet Neurology, but was released Friday to coincide with the meeting presentation.

Ischemic stroke involves an obstruction in one of the vessels supplying blood to the brain. Currently, "clot busters" are only considered effective for the first three hours after a stroke.

"The issue is that we've got a three-hour label, and can we extend that to six hours," said study author Dr. Stephen M. Davis, of Royal Melbourne Hospital. "Based on our results, it gives a lot of encouragement that you can enrich that population. A lot of people arrive too late, and these are ones we would be targeting."

The findings are enough to warrant further trials but not to change current clinical guidelines just yet.

"This should be viewed as very encouraging, as an intermediate step that's leading to the formation hopefully of a larger study that can be more definitive and that could impact our guidelines significantly," said Dr. Philip Gorelick, moderator of the teleconference and head of the department of neurology and rehabilitation at the University of Illinois at Chicago.

A second study looked at patients in China, South Korea and Australia with acute cerebral hemorrhage, the most serious form of stroke.

"High blood pressure is a cause of intercerebral hemorrhage and is also very common at [the] acute state, and we don't know what to do about it," said study author Dr. Craig Anderson, from the University of Sydney in Australia. "We believe that having high blood pressure causes extra bleeding and expansion of blood in the brain. If we can bring blood pressure down, we may be able to arrest bleeding in the brain and bring it under control."

In fact, intensive lowering of blood pressure arrested about half a teaspoon of blood and, Anderson said, "in real life, it might have a bigger treatment effect."

Again, the authors hope the findings will lead to funding for larger trials.

A third trial found that reducing blood pressure in the 60 percent to 70 percent of patients who have elevated levels following acute stroke resulted in reduced dysphasia (communication problems) and some mortality benefits.

"These are very small numbers, and I don't want to hang too much on those results, but I think it's very encouraging, so we can probably go forward and do a much larger phase 3 study," said British study author Dr. John Potter.

For now, Gorelick said, "we continue to recommend that physicians follow American Heart Association/American Stroke Association guidelines. The blood pressure [issue] has not been resolved, and there are important questions of what to do with blood pressure. . . [although] it would be nice to have a definitive plan here and get people on blood pressure-lowering medicine."

Other studies being presented at the conference found that:

• The recently approved Penumbra device, a "vacuum cleaner" which sucks clots out of the brain, was effective for eight hours after the onset of a stroke, adding five hours to a patient's treatment window.
• Aricept (donepezil) improved several measures of executive function and processing speed in patients with a subcortical form of vascular dementia but did not improve overall cognitive scores, according to researchers from the University of Muenchen in Muenchen, Germany.
• Certain chromosomal regions may harbor genes important in assessing individuals at risk for aneurysms. "This is a critical first step if you want to find genes," said study author Dr. Tatiana Foroud, of Medical & Molecular Genetics in Indianapolis. "The ultimate goal is a genetic test to identify individuals at higher risk for aneurysm, and those individuals could have targeted and more costly screening pursued on a regular basis."

More information

Visit the American Stroke Association   for more on different types of stroke.