Heart News and Notes

Moderate alcohol consumption, about two drinks a day, no more, no less, has been associated with better health outcomes, especially less heart disease. A recent study helps explain why. It found that when heart attacks are induced in rats, a toxic byproduct is produced that is neutralized by an enzyme called aldehyde dehydrogenase 2 (ALDH2). This enzyme is already known to eliminate a toxic byproduct of the breakdown of alcohol in your body. Moderate drinkers apparently have more ALDH2. The same study also identified a “small molecule” that enhances the activity of ALDH2.

Chocolate was the subject of another study published last month. Researchers asked people how much dark chocolate they ate and measured the CRP (C-reactive protein) in their blood. People who ate one 20-gram serving every three days, about half a bar a week, no more, no less, had the least CRP. Note that CRP is a marker of inflammation and a predictor of heart disease but is not itself a health outcome.

Results of this study do not apply to milk chocolate. Milk chocolate was not considered because milk is known to interfere with the absorption of polyphenols.

Let’s say you arrive at the emergency room with a suspected heart attack. Two questions have to be answered: are you losing heart muscle, and do you have an obstructed coronary artery?

A recent press release from the European Society of Cardiology points out some of the difficulties. The only sure indication that heart muscle is breaking down is the presence of troponins in the blood; other enzymes can come from other sources. But troponins take three to four hours to become detectable, and you don’t want to wait that long to treat a heart attack. Another problem is that there is no sure test for coronary obstruction.

Help for the first question is on the way. Hypertrophic cardiomyopathy is a condition in which the septum between the left and right ventricles becomes so thickened as to obstruct blood flow. It can be treated with a procedure called septal ablation, which destroys the excess tissue, releasing into the blood the same enzymes as when heart tissue is destroyed in a heart attack.

In a study released online before publication in the October Journal of Clinical Investigation, blood samples were taken from 36 patients before and after septal ablation. Using mass spectrometry, researchers sifted through many substances and identified four that look promising as markers of heart attack. Their hope is that this can eventually lead to a technique that can confirm the occurrence of a heart attack in as little as ten minutes.

Paired trials in a study called GISSI-HF compared PUFA (polyunsaturated fatty acids) and a statin against placebo for heart failure patients getting otherwise standard treatment. Both were randomized trials, the “gold standard” of medical research.

After nearly four years of treatment, the capsule improved survival slightly; the statin didn’t help at all. In one trial, patients given a daily capsule containing one gram of omega-3 fatty acids had 9 percent lower mortality than the control group. In the other trial, patients who got 10 mg of rosuvastatin (Crestor) daily had no improvement in survival. Apparently statins do not address the risks faced by patients with heart failure - and statins cost more than fish oil.

An earlier study by the same group showed a substantial survival advantage for heart attack patients taking omega-3 fatty acids.

Patient history and a physical examination are as good as an invasive right-heart catheterization via the pulmonary artery for estimating how well a heart failure patient is doing, according to a report of the ESCAPE study published last month.

Of 388 patients who got a low-tech assessment, about half also had a right-heart catheterization. The invasive exam did not give a better assessment of outcome over the next six months. It also verified the estimates of fluid accumulation from the low-tech exam.

One reviewer warned that this was a controlled study and might not correspond to actual practice. The lead author in fact noted that physicians might need to become more adept at performing histories and physicals.

We’ve been told at our meetings that glycosylated hemoglobin, also called hemoglobin A1c or HbA_1c, is a good measure of blood sugar control for diabetics. Glucose attaches to hemoglobin gradually, so the amount of HbA_1c in the blood shows the level of blood glucose over the past two or three months.

Studies have observed, even in patients without diabetes, that higher levels of HbA_1c consistently predict greater likelihood of cardiovascular (CV) events. An analysis of data from the CHARM study, published last month in Archives of Internal Medicine, shows that this is true for patients with heart failure.

Among 2412 CHF patients (907 with prior diabetes), with HbA_1c levels ranging from below 5.8 percent to over 8.6 percent, each 1 percent increase in HbA_1c was associated with about a 25 percent increase in total mortality, CV mortality, and hospitalization for worsened heart failure.