July 14, 2011
In a healthy heart, electrical pulses that propagate across the heart muscle in an orderly fashion control the organ’s movements: at regular intervals the heart’s ventricles and atria contract and relax again. In the case of cardiac arrhythmia, however, this does not work reliably. Here, electrical pulses may propagate throughout the heart chaotically, disabling the regular heartbeat and thus preventing the body from being properly supplied with blood. The most common cardiac arrhythmia is atrial fibrillation, which affects more than 10 million people in Europe and US.
For patients suffering from chronic atrial fibrillation there is one reliable solution: a defibrillation. A strong electric pulse, which patients perceive as painful and which can damage the surrounding tissue forces the heart back into its regular beating. The international team of scientists led by Stefan Luther from the Max Planck Institute and Flavio Fenton from Cornell University has proposed a new method. Using a cardiac catheter the researchers create a sequence of five weak electrical signals in the heart. "Only a few seconds later, the heart beats regularly again", says Luther describing the team’s newest results.
Even though LEAP and standard defibrillation seem to work similarly at first sight, they initiate completely different processes within the heart. "The classic defibrillator works by using a very strong electric field that excites all cells of the organ. In contrast, LEAP uses low-energy pulses to synchronize the tissue", says Fenton. For a short moment they can no longer transmit any electrical signals; the chaotic activity is terminated. "Afterwards, the heart resumes its normal, regular beating. The situation can be compared to turning a malfunctioning computer off and on again," says Robert Gilmour from Cornell University.