Figure 5: Myocardial conduction velocity gradient depends on proper integration of FHF with SHF.
From: Chamber identity programs drive early functional partitioning of the heart
(a–e) Vector field maps of control (a) hearts revealing the difference in cardiomyocyte connectivity of outer curvature (OC, red square ROI), presumptive FHF and inner curvature (IC, blue square ROI), presumptive SHF. Hearts of tbx5a (b), pitx2ab (c) morphants and mef2ca mutants (d) show the marked slowing and change from complex to more uniform conduction in OC; partial recovery of these polarities occur in combined mef2ca mutant with loss of pitx2ab (e); unit vector shows the principal direction of propagation. (f) Mean estimated conduction velocities reveal marked deceleration of conduction velocities in tbx5a, pitx2ab morphant and mef2ca mutant hearts. Note the complete loss of the velocity coupling gradient in tbx5a morphant hearts and partial loss in pitx2ab morphant hearts and mef2ca mutants compared with control hearts. The reduction of pitx2ab in mef2ca mutants completely rescued the conduction velocity coupling gradient with marked acceleration of conduction velocities in OC; error bar=s.d., asterisks indicate significance, statistical significance tested with one-way analysis of variance, with Tukey’s post test, P<0.05. All experiments performed at 54 h.p.f.
