Optimal velocity and safety of discontinuous conduction through the heterogeneous Purkinje-ventricular junction

Model Status

This CellML model runs in both COR and PCEnv to reproduce the published results. The CellML model has been based on both the published paper and the original C Code the model was written in. Our thanks go to the authors Oleg and Philip for their help in curating the CellML model and getting it to reproduce their original results.

Model Structure

ABSTRACT: Slow and discontinuous wave conduction through non-uniform junctions in cardiac tissues is generally considered unsafe and pro-arrythmogenic. However, the relationships between tissue structure, wave conduction velocity and safety at such junctions are unknown. We develop a structurally and electrophysiologically detailed model of the canine Purkinje-ventricular junction (PVJ) and vary its heterogeneity parameters in order to determine such relationships. We show that neither very fast nor very slow conduction is safe, and there exists an optimal velocity providing the maximum safety factor of conduction through the junction. The resultant conduction time delay across the PVJ is a natural consequence of the electrophysiological and morphological differences between the Purkinje fibre and ventricular tissue. The delay allows the PVJ to accumulate and pass sufficient charge to excite the adjacent ventricular tissue, but is not long enough for the source-to-load mismatch at the junction to be enhanced over time. The observed relationships between the conduction velocity and safety factor can provide new insights into optimal conditions for wave propagation through non-uniform junctions between various cardiac tissues.

Schematic diagram of the cell model.

The original paper reference is cited below:

Optimal velocity and safety of discontinuous conduction through the heterogeneous Purkinje-ventricular junction, Oleg V. Aslanidi, Philip Stewart, Mark R. Boyett and Henggui Zhang, 2009, Biophysical Journal, volume 97, 20-39. PubMed ID: 19580741