Researchers Keep Heart Rhythm Normal Using Light

We’ve all watched the medical shows when a patient flatlines and doctors race to break out the paddles to restart their heart. The reason giving an electric shock to the heart works is because a heart’s normal sinus rhythm is determined by electrical impulses sent to the cardiac muscles by the body’s nervous system. When these electrical impulses are interrupted or abnormal, it can produce dangerous or fatal contractions of the heart muscles called arrhythmia.

Sometimes arrhythmias can be corrected with using defibrillator paddles, drugs (known as beta-blockers), or the surgical insertion of a pacemaker. These options involve a lot of risks, and provide minimal control over the problem, but there are not a lot of options for fine-tuning that control. Basically, it’s like being able to turn a switch on or off but not being able to dim or brighten the light in a room to a level that’s comfortable.

A desire to gain greater control over these electrical impulses (also known as excitation waves) prompted scientists to look into possible cardiac applications for a field of science known as optogenetics. Optogenetics uses genetic modification to alter cells so that light can activate them. This has been used mainly in brain science, but brain and cardiac excitation waves are very similar. Due to this similarity, researchers decided to test further to see if this method could be a way to fine tune cardiac excitation waves.

To do this, researchers delivered a protein to the heart cells called channelrhodopsin, using gene therapy techniques so that light could control them. Then, using a computer controlled light projector, the researchers were able to control the speed of cardiac waves, the direction and even the orientation of the wave spirals in real time. This is a HUGE development, as in, never been done before!

Short-term benefits include being able to carry out experiments at a level of detail researchers had only been able to carry out via computer-generated models. This gives them the ability to see how well the computer models stack up and provides valuable information on how real cells and the entire heart as an organ work.

Long term? Researchers feel confident that this ability to fine tune excitation waves could conceivably be used to develop more precise treatments for heart conditions. The team is quick to say that there are some significant challenges that must be overcome first, including making sure that they can get the heart to be light sensitized and being able to get the light to desired locations. But with gene therapy, and optical nanotechnology becoming more common, a little innovation will bring us much closer to creating more precise and less invasive treatments for cardiac arrhythmias.

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