Electrical instability in cardiac muscle: phase singularities and rotors

Area of Science:

• Physiology
• Dynamical Systems Theory
• Cardiac Electrophysiology

Background:

• Excitable media exhibit unique pulse propagation behaviors.
• Cardiac muscle shares properties with excitable media, predicting phenomena like rotors.
• Understanding these dynamics is crucial for cardiac function and dysfunction.

Purpose of the Study:

• To investigate the theoretical prediction of paired mirror-image vortices (rotors) in excitable cardiac tissue.
• To experimentally validate the role of stimulus parameters in rotor formation and tachycardia.
• To explore the implications of these findings for cardiac electrophysiology.

Main Methods:

• Theoretical modeling of excitable media dynamics.
• Experimental induction of tachycardia in canine ventricle using controlled electrical stimulation.
• Analysis of rotor formation based on stimulus size and timing ('vulnerability diagram').

Main Results:

• Experimental results support the two-dimensional theory of rotor formation in cardiac tissue.
• Specific combinations of stimulus size and timing were identified as critical for creating rotors.
• Paired rotors, associated with tachycardia, were observed under specific stimulation conditions.

Conclusions:

• The study validates theoretical predictions of rotor dynamics in cardiac tissue.
• Stimulus-induced rotors offer a potential mechanism for tachycardia.
• Further experiments are suggested to investigate three-dimensional vortex filaments in intramural cardiac tissue.