Even though heart attacks may not be deadly, they can leave your ticker damaged. The reason: they occur when blood flow to a section of heart muscle becomes blocked. If the flow of blood isn't restored quickly, a section of the heart muscle becomes damaged from the lack of oxygen and begins to die, weakening its ability to pump blood.

Researchers have long wondered whether such damage could be reversed, that is, whether hobbled heart muscle cells could regenerate — potentially affecting the ability of scientists to hatch ways to repopulate damaged heart tissue. A study in Science today confirms that some heart muscle cells do, in fact, regenerate slowly over the course of a person's lifetime. Scientists from the Karolinska Institute in Sweden report that in early adulthood, we're continually renewing about 1 percent of our heart cells a year; that regeneration slows down, but it still occurs in old age, with a little less than half of 1 percent of cells regenerating at age 75. All told, we've renewed about 40 percent of our heart cells by age 70, neuroscientist Jonas Frisén told Science in a podcast.

WASHINGTON, D.C. (March 10, 2009)—Stem cells have long been touted as potential cures or treatments for a variety of ailments from paralysis to Parkinson's disease. After all, these cells (found in bone marrow, for instance, and also in human embryos, making their use a subject of much controversy) can potentially turn into a wide variety of cells with specific functions. Or, they can throw off proteins—such as growth factors—that help other cells grow. Stem cells injected into a paralyzed patient’s spine, for instance, might help regenerate nerve tissue.

But while the flexibility of these cells is the key to their usefulness, they might not be quite as flexible as we once thought, says Julia Dory Ransohoff, 17, one of 40 finalists in the Intel Science Talent Search here in Washington this week for the competition’s final rounds. (We've been on hand to live-Twitter and to profile a few projects, everything from Splenda in drinking water to whether parents should discuss their drinking with their kids to cellulosic ethanol.)

Cholesterol-lowering statins are the best-selling class of drugs in the country. But as their pool of takers has expanded, critics have complained that the meds, while effective in reducing heart attacks and strokes, haven’t been proved to save lives. 

But new research, published today in the Archives of Internal Medicine, indicates that statins do, in fact, reduce the risk of dying for both people with heart disease and for those who are taking the drugs because their cholesterol is elevated. (Not everyone who suffers a heart attack has high cholesterol, so prescribing statins just because a person's levels are high is controversial.) 

Don't underestimate the value of good bookkeeping. A new study says that your chance of dying and suffering complications is lower in hospitals and clinics that computerize patient charts and drug orders.

There were 15 percent fewer deaths, and patients treated for heart attacks, congestive heart failure or pneumonia or who had coronary bypass surgery were 16 percent less likely to suffer complications in hospitals that kept records in a centralized computer system, according to research published in this week's Archives of Internal Medicine. The findings were based on the records of 167,233 patients aged 50 and older at 72 hospitals in Texas and on doctor ratings of the information technology at those facilities.

The results held even after researchers (from the University of Texas Southwestern Medical Center, Johns Hopkins School of Medicine and the University of Maryland) controlled for the seriousness of conditions and whether a hospital was an academic center or a cash-strapped "safety-net" facility for the indigent.

Ah, sleep. You hardly need a doctor to tell you that getting too little of it can make you irritable and lethargic. Now it looks like how many zzz's you get may affect whether fatty plaque deposits build up in your arteries — a precursor to heart attacks and angina, or chest pain.

University of Chicago docs recorded how much sleep 495 middle-aged folks got over three nights using a monitor worn on their wrists, and examined their hearts for coronary artery calcification using computed tomography (CT) scans. Then the scientists checked back in with them five years later, conducting the same tests.

The good news: U.S. deaths from heart disease and stroke are down by 30 percent, the American Heart Association is reporting. Heart disease deaths fell from 864,480 in 2005 to 829,072 in 2006, the most recent year statistics are available. Stroke deaths declined from 143,579 in 2005 to 137,265 in 2006.

The bad news: heart disease is still the nation’s top killer, and stroke is the third most common cause of death, behind cancer, new research shows. Combined, they account for 34 percent of all deaths.

"It's one of the most remarkable achievements of modern medicine to have this kind of decline," Gregg C. Fonarow, a cardiologist at U.C.L.A.'s Geffen School of Medicine, told the Los Angeles Times. "But there is still obviously a lot of work to be done."

Generic heart medications work just as well as their brand-name counterparts, despite negative commentary on the no-name drugs in medical journals and mainstream media, a new analysis says.

The report in today's Journal of the American Medical Association reviewed 47 head-to-head trials between generic and brand-name versions of heart drugs between 1984 and this year. It found equivalent effects among most medicines in nine drug sub-classes: beta-blockers, diuretics, calcium-channel blockers, anti-clotting drugs, statins, ACE inhibitors, alpha-blockers, anti-arrhythmic drugs (for irregular heartbeats) and warfarin. Americans spend more on those drugs on an outpatient basis than on any other prescription medicines, according to the paper.

It's been a frustrating discrepancy in health for more than a decade: Young women who suffer heart attacks and go to the hospital for treatment have been twice as likely to die as young men. Now, that gender gap is narrowing.

Women under 55 are about 30 percent more likely to die in the hospital after having a heart attack than their male peers, according to research presented yesterday at the American Heart Association conference in New Orleans.

Between 2005 and 2006, 2.4 percent of women under 55 died, a drop from the 5.1 percent who died in 1994 to 1995. Between 2004 and 2006, 1.8 percent of men younger than 55 died in the hospital after experiencing heart attacks, compared with 2.7 percent in 1994 to 1995.

It's been only two months since the American Heart Association (AHA) recommended routine screening of cardiac patients for depression, and already those guidelines are being shot down.

Screening and treating heart patients for depression didn’t improve survival or cardiac health, according to a review of 17 studies published today in the JAMA The Journal of the American Medical Association. In those who showed signs of depression, symptoms improved only slightly — by 1 to 4 percent — with antidepressant drug treatment.

"We cannot in good conscience support screening all heart patients," study co-author Roy Ziegelstein, vice chairman of medicine at Johns Hopkins Bayview Medical Center in Baltimore, said in a statement. "This is a difficult call for us to make, but it is in the best interest of patients at this time" because of its cost, side effects of drug treatment and potentially negative effects of being misdiagnosed as depressed.

Cholesterol-lowering statin drugs are already blockbuster medicines taken by 30 million people around the world. Now it turns out you still might need them if you have normal cholesterol. There’s a new risk factor in town: A protein associated with inflammation.

Taking the statin Crestor, also known as rosuvastatin, slashed the risk of heart attack by more than half in nearly 18,000 people with increased levels of the protein, called high-sensitivity C-reactive protein (CRP), according to research presented yesterday at the annual American Heart Association meeting in New Orleans. The drug reduced the chance of stroke and the need for a stent – a mesh tube propping open the heart’s blood vessels — by nearly 50 percent. It also lowered the risk of death by 20 percent. The research, funded by Crestor maker AstraZeneca, is in this week's New England Journal of Medicine.