Driving patterns of a large non-pacemaker cell by a small pacemaker cell: Associated chaotic and coexisting states

This study deals with the various driving patterns of a large non-pacemaker (NPM) cell (or tissue) by a smaller pacemaker (PM) focus. We used the coupling resistance (CR) as a continuation-bifurcation parameter and a typical cell size ratio of 0.3. Bistability, tristability and associated hysteresis phenomena were evidenced between n:p responses on various computed bifurcated branches. In narrow ranges of value of CR, two types of irregular dynamics can also be found. A classical period doubling bifurcation route and a non-classical (2n+1: n) route both lead to chaos. Thus the interaction between loading phenomena and intercellular coupling may provide a new theoretical framework for interpretation of ectopic focus induced ventricular arrhythmia and fibrillation