Researchers at Johns Hopkins University and Germany’s University of Bonn showed that light can restore a normal heartbeat and replace electric shocks in patients at risk for arrhythmia, according to a press release from the Baltimore school.
The work was published online yesterday in the Journal of Clinical Investigations and could 1 day be used to develop implantable defibrillators, the team suggested.
A standard defibrillator uses electrical shocks to jump-start the heart when a patient experiences arrhythmia, a potentially deadly irregular heartbeat. The shocks can be painful and damage the heart tissue.
Researchers at the University of Bonn turned to the emerging field of optogenetics, which uses light-sensitive proteins to modify electrical activity in cells.
The Bonn team used beating mouse hearts with cells that were genetically engineered to express light-sensitive proteins. By exposing the proteins to blue light, the researchers could alter the electrical activity in the heart.
When they triggered ventricular fibrillation in the beating mouse hearts, they found they could restore a normal heartbeat with 1 second of light.
To determine if it would work with a human heart, the team at Johns Hopkins created a computer model of a human heart, composed of MRI scans from a patient who experienced a heart attack. Instead of blue light, they used red light, which has a longer wavelength and can penetrate human heart tissue.
The simulation showed that beams of red light could stop the cardiac arrhythmia in the patient the model was based on.
“In addition to demonstrating the feasibility of optogenetic defibrillation in a virtual heart of a patient, the simulations revealed the precise ways in which light alters the collective electrical behavior of the cells in the heart to achieve the desired arrhythmia termination,” Natalia Trayanova, the principal investigator from Johns Hopkins, said in prepared remarks.
“The new method is still in the stage of basic research,” added Philipp Sasse, a corresponding author of the study from the University of Bonn. “Until implantable optical defibrillators can be developed for the treatment of patients, it will still take at least 5 to 10 years.”