Artificial Pacemaker

Artificial Pacemaker

Artificial Pacemaker is an electronic device used to increase heart beats when needed in case of failure of the natural electrical system of the heart.

Electrical system of the heart

The heart beats regularly because there is a natural pacemaker for the heart which gives out regular synchronized pulses which causes the heart to contract in a sequence. This pacemaker is known as sinoatrial node or SA node and is situated in the right atrium, the right upper chamber of heart. The pulses are conducted down the atrium to reach a relay station known as the atrioventricular node or AV node. In the AV node the pulse is delayed for a fraction of a second and conducted to ventricles, the lower chambers of heart, through the bundle of His. The bundle of His gives a branch to each ventricle – the left and right bundle branches. The left bundle gives of two smaller branches. All the bundle branches subdivide further and reach very small fibres known as Purkinje fibres. The Purkinje fibres are connected to the heart muscle cells.

When is an artificial pacemaker needed?

When the natural pacemaker or the conduction system of the heart stops functioning properly, the heart rate may fall to dangerously low levels, producing dizziness or loss of consciousness. This situation requires an artificial pacemaker, either temporary or permanent, depending on the reversibility of the disease causing the defect. Commonest disease causing dysfunction of SA node is known as sick sinus syndrome, while the commonest defect of the AV node is known as complete heart block. These are the most common reasons for implantation of a permanent artificial pacemaker. Temporary pacemaker is often required in a myocardial infarction or heart attack with complete heart block.