A perfused canine right bundle branch-septal model for electrophysiological studies

Area of Science:

• Cardiology
• Physiology
• Biomedical Engineering

Background:

• Isolated ventricular muscle preparations deteriorate when perfused with protein-free media.
• Edema and electrical dysfunction occur rapidly in protein-free perfusates.

Purpose of the Study:

• To investigate the effect of colloid oncotic pressure on the electrical characteristics and survival of isolated right bundle branch-septal muscle preparations.
• To determine if adding proteins to the perfusion medium can prevent edema and maintain tissue viability.

Main Methods:

• Isolated right bundle branch-septal muscle preparations were perfused via the anterior septal artery.
• Perfusion solutions included protein-free Tyrode solution, Tyrode solution with bovine albumin, and horse serum.
• Electrical characteristics (transmembrane potential, diastolic potential, action potential amplitude) and edema formation were monitored.

Main Results:

• Perfusion with protein-free Tyrode solution led to rapid edema and loss of transmembrane potential within approximately 6 hours.
• Addition of bovine albumin or horse serum significantly reduced edema formation.
• Intact electrical activity was maintained for over 9 hours in preparations perfused with protein-containing media (P < 0.001).
• Preparations showed improved diastolic potential and action potential amplitude with colloid oncotic pressure.

Conclusions:

• A viable, perfused septal muscle preparation suitable for electrophysiological studies was successfully developed.
• Colloid oncotic pressure in the perfusion medium is crucial for maintaining capillary integrity, preventing edema, and ensuring tissue survival.