About Heart Rhythms
Conduction System
The heart
requires an electrical impulse or signal in order for it to contract
and pump blood throughout the body. The electrical impulse of the
conduction system begins in the sinoatrial node (the hearts natural
pacemaker). The sinoatrial node initiates an electrical impulse that
flows through the right and left atria, making them contract. When the
electrical impulse reaches the atrioventricular node, it is delayed
slightly. The impulse then travels down the Bundle of His, which
divides into the right bundle branch for the right ventricle and the
left bundle branch for the left ventricle. The impulse then spreads
through the ventricles, making them contract.
One heart beat or cardiac cycle refers to the alternating contraction and relaxation of the atria and ventricles. The two atria contract at the same time, then relax, followed by the two ventricles contracting, then relaxing. The contraction phase is called systole. The relaxation phase is called diastole. A well-functioning conduction system is necessary for the heart to contract and pump an adequate supply of blood throughout the body.
Information Guide
About Heart Rhythms
Conduction System
Arrhythmia Overview
Common Arrhythmias
Diagnosing Arrhythmias
Treating Arrythmias
Review Date: 08/06
