Nkx2-5 mutation causes anatomic hypoplasia of the cardiac conduction system
J. Clin. Invest. Patrick Y. Jay, et al. 113:1130 doi:10.1172/JCI19846 [
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Figure 5ECG correlates of anatomic structures in the cardiac conduction system in WT and
Nkx2-5+/– mice. (A) Schematic diagram of the cardiac conduction system and ECG intervals as symbolized by the surface vectors I, II, and III and the intracardiac catheter. (B) Representative surface and intracardiac electrogram from a WT and
Nkx2-5+/– mouse. The upper and middle tracings are simultaneous surface ECGs and IEGMs. The lower tracing shows the intracardiac recording at higher magnification and demonstrates the difference in His bundle signal amplitude between WT and
Nkx2-5+/– mice. Atrial (P, A) and ventricular (QRS, V) depolarizations are depicted. The IEGM shows His (H) depolarization. Atrio-His and His-ventricular intervals are denoted (1 and 2). Note that ventricular depolarization or QRS interval begins immediately after the HV interval. (C) The amplitude of His depolarization is diminished in
Nkx2-5+/– mice at all ages examined (
P < 0.0001 in all age groups). AV, atrial-ventricular; AH, atrio-His; HV, His-ventricular; LBB/RBB, left and right bundle branch; PMJ, Purkinje-myocyte junction; SAN, sinoatrial node; VM, ventricular myocardium.
