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Cardiac Arrhythmias: Difference between revisions
→Phase 1: Early Rapid Repolarization
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===Phase 1: Early Rapid Repolarization=== | ===Phase 1: Early Rapid Repolarization=== | ||
Immediately following rapid depolarization, the inactivation of the Na<sup>+</sup> channel (I<sub>Na</sub>) and subsequent activation of the outward K<sup>+</sup> channel (I<sub>to</sub>) and the Na<sup>+</sup>/Ca<sup>2+</sup> exchanger (I<sub>Na,Ca</sub>) produces a early rapid repolarization. Due to the limited role of the Na<sup>+</sup> channel in the upstroke of sinus node and AV node cells and the subsequent slower depolarization, this rapid repolarisation is not visible in their action potentials (Figure 2). | Immediately following rapid depolarization, the inactivation of the Na<sup>+</sup> channel (I<sub>Na</sub>) and subsequent activation of the outward K<sup>+</sup> channel (I<sub>to</sub>) and the Na<sup>+</sup>/Ca<sup>2+</sup> exchanger (I<sub>Na,Ca</sub>), which exchanges 3 Na<sup>+</sup> for 1 Ca<sup>2+</sup>, produces a early rapid repolarization. Due to the limited role of the Na<sup>+</sup> channel in the upstroke of sinus node and AV node cells and the subsequent slower depolarization, this rapid repolarisation is not visible in their action potentials (Figure 2). | ||
===Phase 2: Plateau=== | ===Phase 2: Plateau=== | ||