Figure 2.
Optical mapping in host-donor strands. A, mCherry fluorescence in donor excitable cells (eg, ExFs) allowed precise identification of host-donor interface with NRVMs. B, Optical recording sites (circles) overlaid on top of cells stained with ANNINE-6plus voltage-sensitive dye. Note small round ExFs in contact with larger elongated NRVMs. Optical mapping revealed progressive APD prolongation across the host-donor interface (representative traces shown from recording sites). Scale bar for sequence of traces at bottom = 75 ms. C-D, Representative isochrone maps of action potential activation (1 ms (C) or 2 ms (D) spacing), repolarization (10 ms spacing), and duration (APD, 10 ms spacing), as well as corresponding spatial profiles of activation and repolarization shown for a representative ExF-NRVM (C) or ExS-NRVM (D) strand. Shown is the 30th propagated AP during 2 Hz pacing. Position of host-donor interface is assigned the coordinate x=0 mm.