Defective cardiac ion channels: from mutations to clinical syndromes
J. Clin. Invest. Colleen E. Clancy, et al. 110:1075 doi:10.1172/JCI16945 [Go to this article.]

Figure 3
Cellular electrical abnormalities and their relation to changes in the ECG. (Left) At fast pacing (heart) rates, mutation-induced changes in epicardial AP morphologies (thick line) cause dispersion of plateau potentials and a voltage gradient (∇V_m, arrow) (WT, thin line). This gradient will manifest on the ECG as ST segment elevation, indicative of BrS. (Middle) Mutations may prolong APD in M cells (thick line) compared to WT (thin line). The delay in repolarization (ΔAPD ∼ 60ms) is reflected as QT prolongation on the ECG, a hallmark of LQTs. (Right) A rightward shift in the Na⁺ channel activation curve is sufficient to reduce AP upstroke and slow cardiac impulse conduction (wide QRS segment) as observed in ICCD. WT, wild-type.