Optical Defibrillation: Light Tames Lethal Heart Disorders in Lab Tests

Using human heart models and experiments with mice, scientists at Johns Hopkins University and Germany's University of Bonn have shown that beams of light could replace electric shocks in patients suffering from a deadly heart rhythm disorder. Their findings could pave the way for a new type of implantable, optical defibrillators. Current devices deliver pulses of electricity that are extremely painful and can damage heart tissue. The researchers say light-based treatment could provide a safer and gentler remedy for patients at high risk of arrhythmia, an irregular heartbeat that can cause sudden cardiac death within minutes. This idea springs from advances in the field of optogenetics, in which light-sensitive proteins are embedded in living tissue, enabling the use of light sources to modify electrical activity in cells.

Transcript

00:00:00 [heart beats above bouncy music] [Natalia Trayanova: We're working towards what we believe is the holy grail.] Achieving an optical defibrillation of the heart where a gentle light will be given to a patient and will completely restore the normal functioning of the heart. Patrick Boyle: A typical electrical defibrillation shock acts very quickly [and almost violently excites the heart terminating the arrhythmia rapidly.] [defibrillator discharging] [Boyle: What we observed in the optogenetic defibrillation process was a gradual slowing of] the arrhythmia which eventually led to termination but without the abrupt punch of a typical electrical defibrillation shock.

00:00:37 [heart beat] [Trayanova: Our collaborators at the University of Bonn were able] to embed light sensitive proteins [in the mouse heart that respond to the light that is delivered to the heart. And that successfully results in the termination of the arrhythmia.] [heart beat] [Trayanova: My lab conducted simulations to show that the arrhythmia in the] much larger human heart can be defibrillated [Trayanova: in the same approach.] Trayanova: So you can see this patient has infarct. [Boyle: We used an actual patient model reconstructed from MRI scans of a patient who had a

00:01:14 a heart attack and was actually vulnerable to arrhythmia.] So what we discovered was that in order to work in the human heart, [Boyle: ostensibly we would need to use red light which is a longer wavelength and is going to penetrate much deeper in the thicker walls of the human heart.] [Trayanova: We're able to offline in the virtual heart to] figure out what is the best option to go forward in terms of what is [the delivery of the light and what is the best way to achieve a certain distribution of these light sensitive proteins.] [Trayanova: But, this is the big initial step that demonstrates that this is possible.] [music ends] [heart beat]