Purkinje Fibers — ECG/EKG Terminology

Definition: The final pathway of the cardiac conduction system. These fibers spread electrical impulses throughout the ventricles, causing them to contract.

Key Facts

• Rapidly conduct impulses through ventricular myocardium for synchronized contraction.
• Normal high-velocity conduction keeps QRS duration narrow.
• Distal conduction disease can produce wide QRS or idioventricular rhythms.

ECG Connection: When Purkinje conduction is delayed, ventricular activation broadens and QRS morphology changes.

Why It Matters: Wide-complex rhythms require fast differentiation between supraventricular and ventricular origin.