Sinus node - the starting of the electrical impulse
Each heartbeat normally occurs in a specialized group of cells called the sinus node. It is located in the upper-right atrium and the heart's natural pacemaker, ie; it is the one that gives the starting signal for each new heartbeat. Sinus node can cause electrical shock or impulse, which is the start of a heartbeat. This is what the heart and other cells, but the sinus node determines the speed of his works, and the heart; they are usually inactive. To describe the standard heart rhythm to normal sinus rhythm doctors.
Wiring harness and the spread of the electrical impulse
From the sinus, node spreads electrical impulses through the heart. When an impulse pass, draws the heart-muscle fibers contract. In a normal heartbeat, impulse spreads first to the right, then in the left atrium after activating atriyadalli down, the tension on the heart and center of the AV node (atrio-ventricular node) that continues. AV node is normally just a hub in the electrical system between the atria and ventricles.
The impulse is delayed approx. tenths of a second in the AV node to the atria time to fill the ventricles with blood. From the AV node, the impulse spreads along two electrical conduction paths (right and left wire bundle), extending beyond the impulse in the right and left ventricle.