Action Potential — ECG/EKG Terminology

Definition: The change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.

Key Facts

• Represents transmembrane voltage changes that drive cardiac depolarization and repolarization.
• Different cardiac tissues have distinct phase behavior and refractory periods.
• Electrolytes and drugs modify action potential duration and conduction velocity.

ECG Connection: QT and ST/T morphology reflect ventricular action potential timing and repolarization behavior.

Why It Matters: Electrolyte or medication changes can become visible on telemetry before clinical collapse.