Fig. 2.

Distinct patterns of alternans at two repolarization levels. A-C) Examples of '++', '+−', and '+0' types of alternans respectively (i.e., shortening plateau corresponds to prolonged, shortened, or unchanged APD at 80% level of repolarization). The three recordings shown were obtained at bcls of 250, 190, and 190 ms respectively. D) Correlation of the difference in consecutive APDs at repolarization levels of 25% and 80%; all tested bcls were pooled together in this plot. E) Composition of the three alternans types in the control condition and following ORM-10962 treatment. The lower total number of entries following ORM-10962 stems from alternans attenuation by the compound: a recording has to manifest alternans of at least 3 ms at the APD25 level in order to be classified as one of the three types. F) A transition matrix encoding the change in alternans type upon ORM-10962 application. Each matrix element colour-codes the number of preparations manifesting a given type of alternans in the control condition (y-axis) that transitioned into a given type of alternans after ORM-10962 application (x-axis).