The Cardiac Electrical System - How the Heart Beats

The Components of the Cardiac Electrical Signal

Figure 1 - the electrical system

Figure 1: The components of the heart's electrical system are illustrated here. From an electrical standpoint, the heart can be thought of as being divided into two portions: the atria (upper chambers), and the ventricles (lower chambers). Separating the atria from the ventricles is a fibrous "disc". This disc (labeled AV disk in the figure), prevents the passage of the electrical signal between the atria and the ventricles. The only way the signal can get from the atria to the ventricles is through the AV node.In this figure, SN = sinus node; AVN = AV node; RA = right atrium; LA = left atrium; RV = right ventricle; LV = left ventricle.

• Introduction to the Cardiac Electrical Signal
• The Components of the Cardiac Electrical Signal
• The Cardiac Electrical Signal Spreads Across the Atria
• The Cardiac Electrical Signal Reaches the AV Node
• The Cardiac Electrical Signal Passes to the Ventricles
• The Cardiac Electrical Signal Spreads Across the Ventricles