Abstract

Light has been used to noninvasively alter the excitability of both neural and cardiac tissue. Here, we demonstrate the first optical pacing of an intact heart in vivo in a method we call optical pacing (OP). Pulsed 1.875 μm infrared laser light was employed to lock the heart rate to the pulse frequency of the laser. A laser Doppler velocimetry (LDV) signal was used to verify the pacing. At low radiant exposures, embryonic quail hearts were reliably paced in vivo without detectable damage to the tissue, indicating that OP has great potential as a tool to study embryonic cardiac dynamics. In particular, OP can be utilized to alter stresses and mechanically transduced signaling by changing the heart rate.

© 2010 Optical Society of America