Conduction System of the Heart

The cardiac conduction system initiates and transmits electrical impulses that trigger myocardial contraction, ensuring efficient heart function.

The process begins at the sinoatrial, or SA node, the heart's primary pacemaker, located where the superior vena cava meets the right atrium.

The SA node generates impulses that travel through internodal pathways in the atria, including the Bachmann's bundle to the left atrium, triggering both atria to contract simultaneously.

These impulses then reach the atrioventricular, or AV node, where a brief delay occurs.

This delay allows the atria to fully contract and the ventricles to fill with blood before ventricular contraction begins.

Following this, the impulses travel down the bundle of His, which splits into the right and left bundle branches, directing the impulses toward the ventricles.

Finally, the impulses reach the Purkinje fibers, spreading the electrical signal throughout the ventricles and triggering a coordinated and synchronized ventricular contraction.

This sequence relies on the properties of automaticity, excitability, and conductivity.