ANATOMY

Detailed explanation-1: -The sinus node is sometimes called the heart’s “natural pacemaker.” Each time the sinus node generates a new electrical impulse; that impulse spreads out through the heart’s upper chambers, called the right atrium and the left atrium (figure 2).

Detailed explanation-2: -The SA (sinoatrial) node generates an electrical signal that causes the upper heart chambers (atria) to contract. The signal then passes through the AV (atrioventricular) node to the lower heart chambers (ventricles), causing them to contract, or pump. The SA node is considered the pacemaker of the heart.

Detailed explanation-3: -The heart’s intrinsic pacemaker, the sinoatrial node (SAN), generates spontaneous action potentials (AP) through a system of coupled oscillators whose common output initiates each normal heartbeat.

Detailed explanation-4: -The sinoatrial node is the natural cardiac pacemaker located in the upper right atrium.

Detailed explanation-5: -A pacemaker is composed of three parts: a pulse generator, one or more leads, and an electrode on each lead. A pacemaker signals the heart to beat when the heartbeat is too slow or irregular.