Tuesday, March 27, 2007; HE04

heart attack

? THE QUESTION Fearing they might contract a disease from mouth-to-mouth breathing or thinking they're not capable of performing cardiopulmonary resuscitation, people sometimes refrain from giving immediate aid to heart attack victims. Might victims benefit if bystanders were to use only chest compressions?

? THIS STUDY analyzed data on 4,068 adults who had a heart attack that was witnessed by ordinary people outside a hospital. About 11 percent were given conventional CPR (mouth-to-mouth and chest compressions) by a bystander, 17 percent were given only chest compressions and 72 percent received no aid until paramedics arrived. A month later, people who had received either type of aid from bystanders were more likely to have survived with good brain function than were those who had to wait for paramedics to arrive. Among heart attack victims with the greatest chance of survival -- those whose hearts could be shocked back to a normal rhythm with a defibrillator -- 22 percent of those who had been given only chest compressions had good brain function after a month, compared with 10 percent of those who had received conventional CPR.

? WHO MAY BE AFFECTED BY THESE FINDINGS? People who witness someone having a heart attack. About 1.2 million people a year have a heart attack in the United States; nearly 40 percent of them die from it within a year.

? CAVEATS The study did not consider the quality of aid administered by bystanders, and it included few instances of heart attacks caused by asphyxia, near drowning or traumatic brain injury. The authors theorized that because chest compressions need to be continuous to improve survival outcomes, the interruption of compressions for mouth-to-mouth in CPR caused the different outcomes. Experts advise that CPR remains vital for people in respiratory distress from near drowning, drug overdose or choking.

? FIND THIS STUDY March 17 issue of the Lancet; abstract available at http://www.thelancet.com.

? LEARN MORE ABOUT CPR at http://www.mayoclinic.com (click on First-Aid); learn about heart attacks at http://www.americanheart.org.

? THE QUESTION Cancer patients have come to expect nausea, fatigue and anemia from radiation or chemotherapy treatments. Might they also experience memory and concentration problems?

? THIS STUDY analyzed data on 595 adults with cancerous tumors treated with radiation, chemotherapy or both. Before treatment, about half reported trouble with concentration or memory. Frequency and severity of problems increased during treatment and remained greater six months later than the pre-treatment level. Overall, about 48 percent of the patients reported concentration problems initially, 67 percent during treatment and 58 percent after six months. Memory loss was reported by 53 percent initially, 67 percent during treatment and 68 percent after six months. People who had radiation only reported less severe symptoms than the others.

? WHO MAY BE AFFECTED BY THESE FINDINGS? People with cancer.

? CAVEATS Cancer patients were not given cognitive tests; data came from the patients' own determination of memory and concentration problems. The authors suggested that the higher-than-normal proportion of people with cognitive problems before treatment may have stemmed from the stress associated with cancer diagnosis or from general anesthesia received during surgery.

? FIND THIS STUDY March issue of the Journal of Oncology Practice; article available at http://www.jopasco.org.

? LEARN MORE ABOUT chemotherapy at http://www.cancer.org; learn about radiation treatment at http://www.cancer.gov.

? THE QUESTION Since no one knows just what causes the blurring of central vision that people older than 60 often develop, it's uncertain how to prevent the disease, known as age-related macular degeneration. Might ARMD be prevented by taking supplements of beta carotene -- an antioxidant present in carrots, which many mothers have urged their children to eat to help their eyesight?

? THIS STUDY randomly assigned 22,071 healthy men 40 and older to take beta carotene supplements (50 milligrams) or a placebo every other day. After an average of 12 years, 549 of the men had developed ARMD. About 60 percent of this group had significant vision loss associated with the disease; nearly a fourth of them had advanced cases. However, there was virtually no difference between the groups: 275 men who took beta carotene and 274 who did not developed ARMD, and results were similar for those with significant vision loss and advanced disease. No harmful effects were reported from the beta carotene.

? WHO MAY BE AFFECTED BY THESE FINDINGS? Older men. Middle-aged people face about a 2 percent chance of developing ARMD, compared with a 30 percent risk for those older than 75. The eye disease is the leading cause of blindness for people 65 and older.

? CAVEATS Beta carotene supplementation is not advised for smokers, in whom it has been shown to increase the risk of cancer. Whether the findings apply to women remains unclear.

? FIND THIS STUDY March issue of Archives of Ophthalmology; abstract available at http://www.archophthalmol.com.

? LEARN MORE ABOUT ARMD at http://www.nei.nih.gov/health and http://www.amd.org.

-- Linda Searing

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.