Sunday, January 30, 2011
Scientists shed new light on how heart works (Australia)
Doctors at the Victor Chang Institute have uncovered new information about the rhythm of the heart and why some drugs might affect that rhythm. Half of all new drugs being developed block one of the channels of the heart and can cause cardiac arrhythmia, which can lead to sudden cardiac death. Professor Jamie Vandenberg, head of the Cardiac Electrophysiology Laboratory at the Victor Chang Institute, says doctors have now found the mechanism which opens the gate to these channels. "Just like a set of metal wires that carry electricity to light up our streets, our body has a series of channels that carry tiny charged particles called ions, into and out of cells, to trigger a heartbeat," he said. "Depending on the position of these gates, many common drugs attach themselves to these channels, blocking the ions from passing through. "This causes what we call Long QT syndrome, where the length of the heart beat is longer than usual, which greatly increases the risk of arrhythmia." Professor Vandenberg believes the "gate mechanism" will also apply to other channels important in the heart's electrical system, as well as those that control electrical communication in the brain.