Figure 1.

(A) Typical ECG recording (top) and optically mapped action potential (bottom) in adult zebrafish heart. Adapted from Tsai et al. (2011), with the permission of Elsevier. (B) Typical atrial (top) and ventricular (bottom) action potentials recorded from spontaneously beating intact zebrafish hearts. Adapted from Nemtsas et al. (2010), with the permission of Elsevier. (C) Typical intracellular Ca²⁺ transient measured within a Fluo-4-loaded isolated ventricular myocyte. Adapted from Zhang et al. (2011), with the permission of the American Physiological Society.