Sistema de Conducción Cardíaca

What is the Cardiac Conduction System?

Overview of the Cardiac Conduction System

• The cardiac conduction system consists of modified muscle cells capable of generating and propagating electrical impulses throughout the heart's musculature.

• These cells are organized into two main types: circular or nodular (e.g., sinoatrial node and atrioventricular node) and branched pathways that facilitate electrical signal propagation.

Functionality of the Sinoatrial Node

• The conduction process begins at the sinoatrial (SA) node, located at the junction of the superior vena cava and right atrium, which generates impulses to maintain optimal heart rate.

• The SA node typically discharges at a frequency of 60 to 100 beats per minute, influenced by sympathetic or parasympathetic stimuli affecting heart rate.

Atrioventricular Node Role

• After impulse generation in the SA node, signals travel through various tracts to reach the atrioventricular (AV) node, which serves as a backup pacemaker if needed.

• The AV node generally maintains a lower heart rate of 40 to 55 beats per minute when functioning independently due to potential issues with the SA node.

Impulse Transmission Through Heart Structures

• Upon reaching the AV node, impulses must traverse through the cardiac septum, ensuring separation between heart chambers and preventing blood contamination.

• This anatomical division allows for a physiological delay necessary for proper blood flow from atria to ventricles before contraction occurs.

Final Pathways and Purkinje Fibers

• The impulse then divides into left and right pathways; specifically, it branches further on the left side into anterior and posterior fascicles for uniform electrical stimulation.