Heart News and Notes

Some recent small trials show promising results for a quick and easy stress test developed by an Israeli company, and a large Phase 3 trial is underway in the U.S. The procedure takes about two minutes and can be done at a patient’s bedside or in a doctor’s office.

A photoplethysmograph finger probe (like the device clipped on a patient’s fingertip to measure blood oxygen level) is connected to a computer. The patient breathes normally for 20 seconds, and then takes deep breaths at six breaths per minute for 70 seconds. Spectral analysis of the output immediately determines the RMR (respiratory modulation response).

The trials show that RMR is lower in patients with coronary artery blockage, and improves after angioplasty opens the blockage. RMR seems to show the effect of arterial blockage on blood flow.

Last month The Washington Post described a new version of the Atkins diet (which blames carbohydrates, just like the old one), citing a metastudy in the American Journal of Clinical Nutrition that says there’s no evidence that saturated fat is bad for your heart.

The Post also mentioned another study in the same journal that might explain that result. When you ask whether saturated fat is bad, you have to ask “compared with what?” Replacing dietary saturated fat with polyunsaturated fat lowers the risk of coronary events. Replacing it with refined carbohydrates increases the risk. Mixing these strategies will give inconsistent results.

Recommending a “low fat” diet pushes people toward carbohydrates, possibly including refined carbohydrates. It’s time to go beyond “low fat” vs. “low carb” and emphasize unsaturated fats and whole grains.

An article on this page just a year ago reported disappointing results from a randomized trial called STICH (surgical treatment of ischemic heart failure), designed to test a procedure for downsizing and reshaping enlarged hearts along with coronary bypass.

A new analysis focused on the patients whose hearts were accurately measured four months after surgery, grouping them according to the size of their hearts before surgery. No subgroup showed any significant difference in outcomes (angina, heart failure symptoms, exercise tolerance, mortality or hospitalizations) between patients who had the reshaping surgery and those who only had bypass.

It seemed like a good idea, but the researchers observed that while the hearts of patients who only got bypass grew smaller in the months after surgery, the reshaped hearts gradually expanded toward their former size.

Warfarin (brand name Coumadin) is prescribed for atrial fibrillation patients to prevent blood clots that could cause strokes, but dose management is difficult. Some experts believe that two experimental anticoagulants, dabigatran and the newer betrixaban, will bring in a “post-warfarin” era, as they promise to be as effective as warfarin with less bleeding.

Another approach is to base the warfarin dosage on tests for two genes that affect warfarin metabolism and Vitamin K activation. Patients tested for these genes had 28 percent fewer hospitalizations for bleeding and clotting than historical controls, but it’s not clear whether the improvement was due to testing or to more attention paid to (and by) those patients.

Plavix (clopidogrel) is prescribed along with aspirin after implanting stents. The FDA issued a strong warning last month that Plavix may be ineffective in those few patients who can’t metabolize it to its active form. Cardiologists protest that they have no good alternative.

Meanwhile, a group is testing triple antiplatelet therapy after stenting, adding Pletal (cilostazol) to Plavix and aspirin. Their tests show less platelet activity without increased bleeding.

Six months ago on this page we reported a study in Italy that found coffee to be associated with atrial fibrillation. On the other hand, a Danish study mentioned in a report of a new study last month did not show any association.

Large doses of caffeine are known to disturb the heart rhythm, but that says nothing about normal coffee intake. The new study, which followed over 130,000 people, found that those who said they drank four or more cups a day had 18 percent lower risk of hospitalization for all major types of heart rhythm disturbances, while those who had one to three cups had a 7 percent risk reduction.

But since this was an observational study it can’t identify cause and effect. Besides, different studies still tend to show inconsistent results.

Last October this page carried a report that although obese people had more heart attacks and heart failure, once they had heart trouble they were more likely to survive than people of normal weight. A recent study at the University of Rochester has confirmed this “obesity paradox.”

A study in Sweden adds to this a blood pressure paradox: among patients admitted to the ICU with chest pains, the higher their blood pressure, the more likely they were to survive - even at systolic pressures as high as 200.

Some experts were not surprised. High blood pressure in the doctor’s office is a known risk factor. But inability to raise blood pressure in response to stress is also a risk factor, and these patients were under stress when their blood pressure was measured in the ICU.