August 24, 2009

Cholesterol may cause cardiac arrhythmias

Cholesterol can affect the flow of the electrical currents that generate the heart beat, causing cardiac arrhythmias, researchers in Canada and France said.

Scientists had long known cholesterol plays an important role in regulating the heart's electrical system, but they didn't know how.

University of British Columbia researchers David Fedida and Jodene Eldstrom along with researchers in Paris found that too much cholesterol can affect the electrical currents, perhaps causing the heart to start beating out of rhythm or even stop beating.

In addition, the researchers found reducing the cholesterol normalized the structures underlying the electrical activity -- promoting a regular heartbeat.

The study, published in the Proceedings of the National Academy of Sciences, said the key mechanism by which cholesterol affects cardiac arrhythmias is the Kv1.5 potassium channel, a protein that facilitates the flow of electrical charges through heart cells.

Cholesterol blocks the functioning of these proteins while lowering of cholesterol levels enhances their function, the study said.