Correcting the irregular heartbeat of an arrhythmia with a standard defibrillator can be a shocking experience that jolts the patient and sometimes leaves residual damage to the very heart muscle that the technique is trying to fix. A team of researchers from John Hopkins University hopes to change this by developing a kinder and gentler process that uses light pulses — directed toward the heart — to fix an arrhythmia without any significant damage to the heart.
The Optogenetics defibrillator can reset a heart arrhythmia using a gentle pulse of light that corrects the arrhythmia slowly instead of through the jolting punch used by the electrical shock method. According to biomedical engineering professor Natalia Trayanova, the research team at Johns Hopkins University “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.”
Working in conjunction with Johns Hopkins, researchers at the University of Bonn in Germany tested the new optical defibrillator method on mice. In these experiments, the mouse subjects were genetically engineered to contain light-sensitive proteins in their heart muscle. When exposed to as little as a one-second pulse of light, the light-responsive proteins were able to gradually slow down the heart’s electrical activity, eventually restoring a healthy heartbeat.
Using information gleaned from the mice trials, the researchers at John Hopkins developed a human model counterpart using data from an MRI scan of a patient who had a heart attack and was susceptible to arrhythmia. The team found that the longer wavelength red light was best at penetrating the heart muscle, in contrast to the blue light that was used in the mouse trials. “Our simulations show that a light pulse to the heart could stop the cardiac arrhythmia in this patient,” says Patrick M. Boyle, a Johns Hopkins biomedical engineering research professor who was also a lead author of the journal article. This model shows the potential utility of an optical defibrillator and cardiac optogenetics, but the technology is still in its infancy and additional research is needed before the device can be produced for clinical use.