Gentle beams of light can treat lethal heart disorders

New York: Gentle beams of light could replace harsh electric shocks in patients reeling from a deadly heart rhythm disorder, new research has found.

Current devices deliver pulses of electricity that are extremely painful and can damage heart tissue. 

Light-based treatment should provide a safer and gentler remedy for patients at high risk of arrhythmia, an irregular heartbeat that can cause sudden cardiac death within minutes, the researchers said.

"We are working towards optical defibrillation of the heart, where light will be given to a patient who is experiencing cardiac arrest, and we will be able to restore the normal functioning of the heart in a gentle and painless manner," said one of the researchers Natalia Trayanova, Professor at Johns Hopkins University, Baltimore, Maryland.

To move the new heart treatment closer to reality, the scientists at Johns Hopkins and Germany's University of Bonn focused on two different types of research.

The Bonn team conducted tests on beating mouse hearts whose cells had been genetically engineered to express proteins that react to light and alter electrical activity within the organ.

When the researchers triggered ventricular fibrillation in a mouse heart, a light pulse of one second applied to the heart was enough to restore normal rhythm.

"This is a very important result," one of the lead authors of the study Tobias Bruegmann from the University of Bonn said.

"It shows for the first time experimentally that light can be used for defibrillation of cardiac arrhythmia," Bruegmann noted.

To find out if this technique could help human patients, the Johns Hopkins team performed an analogous experiment within a detailed computer model of a human heart, one derived from MRI scans taken of a patient who had experienced a heart attack and was now at risk of arrhythmia.

"Our simulations show that a light pulse to the heart could stop the cardiac arrhythmia in this patient," Patrick Boyle from Johns Hopkins University said.

To do so, however, the method from the University of Bonn had to be tweaked for the human heart by using red light to stimulate the heart cells, instead of the blue light used in mice, the researchers said in the study published online in The Journal of Clinical Investigation.

The blue light used in the much smaller mouse hearts was not powerful enough to fully penetrate human heart tissue. The red light, which has a longer wavelength, was more effective in the virtual human tests, Boyle explained.

The findings could pave the way for a new type of implantable defibrillators.