Basis for the Induction of Tissue-Level Phase-2 Reentry as a Repolarization Disorder in the Brugada Syndrome

Figure 3

Dependence of the induction of phase-2 reentry (P2R) on different factors. (a) Unsuccessful attempt to initiate P2R. In this case, the action potential was prolonged, and sodium availability in the lost-dome region (red) has not recovered sufficiently for P2R to occur. (b) Successful P2R facilitated by reduced electrical coupling: other parameters remain as in (a). (c) Successful P2R under the same conditions as (a) except for a slight increase in the delay before formation of the dome in the delayed-dome region (blue). Wave profiles show details in the 1 cm region around the lost-dome and delayed-dome interface. Black indicates excited areas, light blue areas with fast inward channel availability, and green areas where fast inward channels are available and voltage has been brought above activation threshold. The red dashed line shows the fast inward current inactivation gate. For P2R to occur, part of the lost-dome region must repolarize, recover from fast inward channel inactivation, and then be brought above the excitation threshold through diffusive currents generated by the delayed-dome region.

(a)

(b)

(c)