Optical mapping of Langendorff-perfused rat hearts

Area of Science:

• Cardiovascular Physiology
• Biomedical Imaging
• Electrophysiology

Background:

• Optical mapping with voltage-sensitive dyes is crucial for studying cardiac electrical activity in various experimental models.
• Advancements in high-speed cameras and voltage-sensitive dyes enable practical electrical signal acquisition for cell biologists.
• While CMOS cameras offer high frame rates, traditional methods like CCD cameras provide advantages in dynamic range and signal-to-noise ratio.

Purpose of the Study:

• To demonstrate a practical method for optical mapping of cardiac electrical activity in ex vivo rat hearts.
• To visualize and record action potentials on the cardiac surface using voltage-sensitive dyes and high-speed imaging.
• To correlate optical mapping data with simultaneous electrographic recordings.

Main Methods:

• Lewis rat hearts were perfused ex vivo using a modified Langendorff apparatus with Krebs-Henseleit solution.
• Hearts were treated with 2,3-butanedione monoxime to minimize motion artifacts during imaging.
• Hearts were loaded with di-8-ANEPPS dye and illuminated, with emitted light captured by a high-speed CMOS camera.
• Pacing was achieved using a coaxial electrode, and simultaneous bipolar electrograms were recorded.

Main Results:

• Action potentials on the surface of Langendorff-perfused rat hearts were successfully visualized.
• Optical mapping signals were acquired with high spatiotemporal resolution.
• Simultaneous electrographic recordings provided validation for the optical mapping data.

Conclusions:

• Optical mapping provides a powerful tool for visualizing cardiac action potential propagation in ex vivo models.
• The described method allows for the integration of optical and electrographic data for comprehensive cardiac electrical analysis.
• This technique is valuable for investigating normal cardiac rhythm and arrhythmias.