Figure 2.

Extension of cable analysis to action potential wavelength, wave-break, and re-entry. A: typical murine monophasic right ventricular action potential (AP) waveform, indicating basic cycle length (BCL), action potential duration at 90% recovery (APD₉₀), latency and diastolic interval (DI) of the current (n^th) and preceding [(n−1)^th]AP. B: these variables yield the active and resting wavelengths λ' and λ₀' for which the basic cycle distance, BCD' = λ' + λ₀'. C: orthograde propagation of an AP with long λ' over a heterogeneity results in the back of the propagating wave blocking retrograde propagation. D: propagation of an AP with a short λ' results in the back of the wave passing the heterogeneity before retrograde excitation has crossed the unidirectional block. This results in initiation of a new propagating retrograde wave and a re-entrant circuit. [From Matthews et al. (753).]