Fig. 6

Ventricular cardiac electrical action potentials are affected in hadp1 morphants. (A-E) Optical mapping of voltage activation in the zebrafish heart. (A) Sequential images of an ex vivo wild-type heart at 48 hpf show the initiation of an electrical impulse from the sinoatrial (SA) node (left-side), as illustrated by the increased color in the left-most panel. Serial images show the propagation of electrical activation across the heart, through the atrium to the AV node, to the ventricle, and through the outflow tract. Lower panels, corresponding to those above, show the morphology of ventricular fluorescence during the course of a single round of impulse propagation. (B) Representative traces of action potentials from single sites in the atrium of control (black) and hadp1 morphants (red). The atrial action potential duration (APD80) is quantified in C. (D) Representative traces of action potentials from single sites in the ventricle of control (black) and hadp1 morphants (red). The ventricular action potential duration (APD80) is quantified in E.