Conduction velocity of cardiac tissue.
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cardiac tissue conduction velocity SA node AV node atrium ventricle Purkinje m/s physiology
Reading File
Conduction velocity in cardiac tissues
| Cardiac tissue | Approximate velocity |
|---|---|
| SA node | 0.05 m/s |
| Atrial pathways / atrial muscle | 1 m/s |
| AV node | 0.01-0.05 m/s |
| Bundle of His | 1 m/s |
| Purkinje fibers | 2-4 m/s |
| Ventricular muscle | 0.3-1 m/s |
Order, slowest to fastest:
AV node ≈ SA node < ventricular muscle < atrial muscle / His bundle < Purkinje fibers.
AV node ≈ SA node < ventricular muscle < atrial muscle / His bundle < Purkinje fibers.
Why it matters
- AV nodal slow conduction produces the AV delay, allowing atrial contraction and ventricular filling before ventricular systole.
- Purkinje fibers conduct fastest, allowing rapid, coordinated activation of both ventricles.
- Conduction is faster in tissues with a rapid phase-0 upstroke mediated mainly by fast Na⁺ channels, larger fiber diameter, and more effective gap-junction coupling. Nodal tissue relies predominantly on slower Ca²⁺-dependent depolarization.
Values vary slightly among physiology texts and depend on the precise region measured. Medical Physiology lists SA node 0.05, atrial pathways 1, AV node 0.05, His bundle 1, Purkinje system 4, and ventricular muscle 1 m/s.
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