Automaticity — ECG/EKG Terminology

Definition: The ability of cardiac cells to spontaneously generate an electrical impulse.

Key Facts

• Ability of cardiac pacemaker cells to depolarize spontaneously without external input.
• SA node has highest normal automatic rate and typically suppresses lower foci.
• Enhanced automaticity can produce ectopic atrial, junctional, or ventricular rhythms.

ECG Connection: Ectopic automatic foci produce premature or escape beats with characteristic morphology changes.

Why It Matters: Distinguishing automatic rhythms from reentry or triggered activity guides escalation urgency.