In Brief

Of Oxidative Stress Can Predict Risk Of Atrial Fibrillation

Measuring oxidative stress may help doctors predict the risk of developing atrial fibrillation, the most common heart beat irregularity. Emory researchers have identified a connection between oxidative stress and enlargement of the heart’s left atrium, which leads to atrial fibrillation.

People with high levels of the amino acid cystine in their blood at the start of the study were two times more likely to develop atrial fibrillation over the next three years, even after correction for traditional risk factors. Leakage from a heart valve also increased the risk.

“Our results suggest that increased oxidative stress promotes remodeling of the heart and enlargement of the left atrium, which can increase the likelihood of atrial fibrillation,” says Nima Ghasemzadeh, an Emory cardiology researcher. “Studies targeting oxidative stress markers may have a valuable effect in reducing atrial fibrillation risk.”

Antidepressants linked to thicker arteries

Antidepressant use may lead to thicker arteries and contribute to an increased risk of heart disease, according to a study by Emory cardiology researchers.

Researchers studied male twins who both served in the Vietnam War to separate the effects of antidepressants from the depression itself, which also can heighten the risk of heart disease. The twin who took antidepressants had higher carotid intima-media thickness, even with standard heart disease risk factors taken into account.

“One of the strongest and best-studied factors that thickens someone’s arteries is age, and that happens at around 10 microns per year,” says Amit Shah, a cardiology fellow. “In our study, users of antidepressants saw an average 40-micron increase in intima-media thickness, so their carotid arteries are in effect four years older.”

Antidepressants’ effects on blood vessels may come from changes in serotonin, Shah says. Some antidepressants increase the level of serotonin in the brain, but serotonin also is found in the intestines and in platelets. Serotonin can cause blood vessels to constrict or relax, depending on whether the vessels are damaged.