Fig. 3
From: The long QT syndrome family of cardiac ion channelopathies: A HuGE review
Ionic currents/LQT gene products and the ventricular action potential. Vertical axis represents voltage; horizontal axis represents time. The initial upstroke (phase 0), rapid depolarization, occurs through the rapid inflow of sodium (INa). The peak, rapid repolarization (phase 1), is mediated by a transient outward potassium current, Ito. The plateau (phase 2) reflects a balance between inward sodium and L-type calcium currents (ICa,L), and outward potassium (IKs, IKr) and chloride currents (not shown). Increasing conductance of rapid potassium current (IKr) completes repolarization (phase 3) together with contributions from the slow potassium current (IKs) and inward rectifying current (IK1). The cell then returns to its baseline resting potential (phase 4) until the next upstroke. The LQT gene products depicted in parentheses encode most of the ion channel proteins mediating these currents. Modified from Roden DM, Spooner PM. J Cardiovasc Electrophysiol 1999,3 with permission of Blackwell.
