Afterdepolarizations are best defined as?

• A. Normal Voltage Changes During The Cardiac Action Potential
• B. Abnormal Secondary Voltage Depolarizations During The Cardiac Action Potential
• C. Depolarizations Of Atrial Myocardium Only
• D. Hyperpolarizations At Rest

Answer: (B)

Afterdepolarizations are abnormal secondary depolarizations that occur in relation to the cardiac action potential. They are extra depolarization events that happen during or after repolarization, not part of the normal voltage changes. They come in two forms: early afterdepolarizations, which occur during the plateau or early repolarization, and delayed afterdepolarizations, which occur after full repolarization and are often tied to calcium overload. This definition captures why they can trigger arrhythmias, unlike normal action potential phases, depolarizations restricted to the atria, or resting hyperpolarizations.