Mechanisms of sinoatrial pacemaker synchronization: a new hypothesis.

摘要: A model of electrically coupled sinus node cells was used to investigate pacemaker coordination and conduction. Individual were simulated using differential equations describing transmembrane ionic currents. Intrinsic cycle lengths (periods) adjusted by applying constant depolarizing or hyperpolarizing bias current, through ohmic resistances form two-dimensional arrays. Activation maps 81-225 showed an apparent wavefront conducting from a leading region the rest matrix even though pattern actually resulted mutual entrainment all spontaneously beating cells. Apparent conduction time increased with increasing intercellular resistance. Appropriate selection permitted accurate simulation activation sequence seen experimentally for rabbit node. Furthermore, acetylcholine pulse applied randomly selected 20% in this produced shift that lasted several beats. These results support hypothesis synchronization occurs "democratic" process resulting phase-dependent interactions thousands pacemakers.