Faulty electrical signaling in the heart causes arrhythmias
What are cardiac arrythmias?
The heart has its own electrical system that controls the speed and the rhythm of every heartbeat. With each heartbeat, an electrical signal spreads from the top of the heart to the bottom. As it travels, the electrical signal causes the heart to contract in an organised manner and pump blood.
Electrical signals normally begin in a group of cells called the sinus-atrial (SA) node. As these signals spread from the top to the bottom of the heart, they coordinate the timing of heart cell activity. First, the two upper chambers of the heart, called atria contract.
This contraction squeezes blood into the lower chambers of the heart, which are called ventricles. The ventricles then contract and send blood to the rest of the body. The combined contraction of the atria and ventricles is a heartbeat.
The first image shows the heart and its blood flow. The second image shows an example showing heart block
Sometimes the heart beats too slowly (Bradycardia). During Bradycardia, enough blood is not supplied to the body, due to failure of the hearts chambers to contract properly.
This could happen due to SA node not functioning properly, or by a condition called heart block. In this condition, a problem exists with the electrical pathway between the atria and ventricles. Electrical signal sent out by the SA node may not reach the ventricles or is delayed.
Faulty electrical signaling in the heart causes arrhythmias. A pacemaker uses low-energy electrical pulses to correct faulty electrical signaling. Pacemakers can speed up a slow heartbeat, Pacemakers can also coordinate the electrical signaling between the upper and lower chambers of the heart. The device will make sure the ventricles contract normally if the atria are quivering instead of beating in a normal rhythm (a condition called atrial fibrillation).