DN Vinculin overexpression impairs valve function. (A–D) Still images of beating hearts from WT (A and C) and DN Vinculin–overexpressing (B and D) larvae. Images were taken from videos that comprised one ventricular contraction (a duration of ∼40 ms). Larvae at 77 (A and B) and 100 (C and D) hpf are shown. WT valve leaflets closed the AVC for ∼30 ms per contraction, whereas AVC leaflets in DN Vinculin–overexpressing larvae did not close efficiently and did not prevent retrograde blood flow. Scale bars: 20 µm.