Heart News and Notes

Cardiorespiratory fitness declines throughout adult life, but at an accelerating rate after age 45, and the rate of decline is faster if you’re inactive, obese or a smoker, according to a study at the University of Houston.

A research team analyzed data from the Aerobics Center Longitudinal Study. Over 20,000 men and women were each tested several times on a treadmill, to determine their maximum energy expenditure in METs, weighed and measured to find their BMI, and asked about their activity level and smoking.

Overall, by age 80 both men and women had about 65 percent of their former peak fitness. Fitness fell by about 0.3 METs from age 40 to 59; from age 70 to 79, the drop was 1.4 METs for women and 1.6 METs for men. Smoking, and each unit of BMI, cost another fraction of a MET, while activity could gain a MET or more.

According to a report by Dr. Kenneth Madden at the 2009 Canadian Cardiovascular Congress, three months of physical activity can help older patients - specifically adults age 65 to 83 with Type 2 diabetes, high blood pressure and high cholesterol - by making their arteries less stiff and their artery walls more elastic, compared with those who didn’t get the activity.

The patients were classified as sedentary at the beginning of the study and gradually increased to 70 percent of maximum heart rate. “People always underestimate what older adults can do,” Dr. Madden said.

Headphones on your head are harmless. But about an inch or less from the skin over an implanted defibrillator or pacemaker, they can make the device malfunction.

All headphones have permanent magnets that create a magnetic field even when not plugged in. Close to an ICD they can temporarily close a reed switch and disable the device, and in one case the device had to be reprogrammed.

You can use headphones safely if you have an ICD; just don’t drape them around your neck or put them in a breast pocket.

So says an article on an analysis of four-year data from TYCOON (Two-Year Clopidogrel Need), but the investigators themselves are not so sure. It’s still not clear how long you have to take Plavix after a drug-coated stent. Total thromboses (coronary events due to blood clots) were 0.7 percent after a bare metal stent; for a drug coated stent they were 3 percent with one year of clopidogrel, but only 0.4 percent with two years of the drug.

But these events are rare, all the published studies are undersized, and the numbers are so small that the differences could be random. The results, according to one of the researchers, are “hypothesis generating,” not definitive. If you were confused, don’t change.

A new analysis of MESA (Multi-Ethnic Study of Atherosclerosis) confirmed that calcium score (a controversial indicator derived by coronary CT angiography) is a good screening test for coronary artery disease. But it should not be relied on when a patient comes in with chest pain, because it doesn’t detect soft plaque.

MESA enrolled 6,814 patients with no known heart disease. More than half, 3,563, had zero calcium score. Catheterization, which measures blockage directly, was done on 175 patients in the first six years of the study, most of them because they developed symptoms. Of those who had significant coronary artery narrowing (stenosis), seven originally had zero calcium score.

That’s only 0.2 percent of the zero-calcium-score group, which says zero calcium score implies low risk; the other group had about 95 percent of the serious stenoses. But it’s four percent of those who needed further testing, which shouldn’t be ignored.

You thought - we all thought - arterial plaque never went away. An imaging study reported early this month found that niacin, given to patients also getting statins, not only increased HDL but also reduced the area of plaque in coronary arteries. However, it’s not clear whether the most dangerous part of the plaque was reduced. Another study report expected later this month compares niacin with Zetia, and niacin is expected to win.

Enlarged hearts in heart failure patients can also be reversed. Beta blockers can shrink enlarged hearts but they can also weaken the heartbeat. Another class of drugs, phosphodiesterase (PDE) inhibitors, could also shrink enlarged hearts. This class includes Viagra, a PDE5 inhibitor, but PDE1 inhibitors might be more effective, perhaps in combination with beta blockers. Tests are now being conducted in live mice.

Women do have the same heart attack symptoms as men, says a study reported to the Canadian Cardiovascular Congress 2009, contradicting a host of previous studies. Other studies have found that women with heart attacks present with different symptoms and respond differently to treatment, suggesting that men and women have different kinds of heart attacks.

This study didn’t look at real heart attacks. It simulated the classic kind of heart attack that men get, by inflating a balloon in a coronary artery (as in angioplasty or stenting). Women experiencing this simulated heart attack reported - with minor differences in emphasis - the classic chest pain symptoms common in men.

The presenter suggested that the other studies are wrong because of miscommunication in a clinical setting. Your editor is puzzled. If women with classic heart attack report classic symptoms, then when they report different symptoms they must be having a different kind of heart attack.