Contraction — ECG/EKG Terminology

Definition: The tightening and shortening of a muscle.

Key Facts

• Mechanical shortening follows electrical depolarization through excitation-contraction coupling.
• Electrical activity can persist without effective mechanical output in severe illness.
• Contractile strength is influenced by preload, afterload, and inotropy.

ECG Connection: ECG reflects electrical events, not direct stroke volume; organized rhythm does not always mean perfusion.

Why It Matters: Always correlate telemetry with pulse and blood pressure.