Propagation through electrically coupled cells: two inhomogeneously coupled cardiac tissue layers

Area of Science:

• Cardiac Electrophysiology
• Computational Biology

Background:

• Purkinje (P) cells facilitate rapid ventricular (V) activation.
• P-V junctional regions exhibit spatially inhomogeneous conduction properties.

Purpose of the Study:

• To investigate the impact of spatially inhomogeneous electrical coupling on P-V cell layer conduction.
• To model conduction block and velocity variations observed experimentally.

Main Methods:

• Extended 1D simulations to a double-layer model of excitable cells.
• Incorporated spatially inhomogeneous electrical coupling between P and V layers.

Main Results:

• Partial uncoupling can increase conduction velocity and enable P-to-V conduction where block would otherwise occur.
• Simulated spatial distributions of coupling resistivity match experimental observations of variable conduction block.
• Inhomogeneous coupling can enhance ventricular activation velocity and safety.

Conclusions:

• Regional electrical coupling is a crucial design feature for efficient ventricular activation.
• Increased uncoupling, as in ischemia, may underlie the development of cardiac arrhythmias.