A pacemaker is a small device which consists of two parts. They are a generator and wires ( leads or electrodes) that are placed under the skin in your chest to aid in the control of your heart beats.
People may require a pacemaker for a number of reasons mostly because of a condition called arrhythmias in which the heart’s rhythm is abnormal.
Normal aging of the heart can also cause disruption of your heart rate, making it beat slow. Damage of heart muscle due to a heart attack is also another common cause of irregular heartbeat.
Generally, a pacemaker is implanted in your chest with minor surgery. You may have to take a couple of precautions in your day to day life after the implantation of the pacemaker.

Why is it done

Pacemakers are implanted so that they can help to control your heartbeat. They may be implanted temporarily to treat slow heart rhythm after a heart attack, surgery or drug overdose.
Sometimes, pacemakers can be implanted permanently to rectify slow heartbeat or to treat heart failure.
Small pacemakers that are about the size of the pill have been developed and are currently undergoing clinical trials.

How your heart beats

To understand how a pacemaker works, it is useful to know how your heart beats.
The heart is a fist-sized muscle pump with four chambers, two on the left side and two on the right side. The upper chambers are the right and left atria. The lower chambers of the heart are the left and right ventricles.
For the heart to function properly, the heart chambers must function in a coordinated manner. Your heart should also beat at an appropriate pace, usually 60 to 100 beats per minute in adults at rest. If your heart beats too slowly or too quickly, there is not enough blood flowing through your body, which causes fatigue, fainting, shortness of breath, confusion and other signs and symptoms.
Your heart's electrical system controls the pumping action of the chambers. A normal heartbeat begins in the right atrium, in the sinus node. This group of cells, the natural pacemaker, acts like a spark plug and generates regular electrical impulses that travel through specialized muscle fibers.
When an electrical impulse reaches the right and left atrium, it contracts and compresses the blood in the ventricles. After a delay of a fraction of a second to allow the ventricles to fill, the impulse reaches the ventricles, causing them to contract and pump blood towards the rest of the body.

What a pacemaker does

An implanted pacemaker imitates the action of the natural pacemaker that is the sinoatrial node. The electronic pacemaker has two parts. They are

• The pulse generator: The pulse generator is a small metal house container which contains a battery and electrical circuitry that manages the rate at with the electrical pulses reaches the heart.
• Leads or Electrodes: One to three adjustable, insulated wires are each placed in a chamber or chambers of your heart and deliver the electrical pulses to adjust your heart rate.

The pacemaker monitors your heartbeat and if it is too slow, the pacemaker will speed up the heartbeat by sending electrical signals to your heart. Also, most pacemakers have sensors which detect the body motion or breathing rate and signals the pacemaker to increase your heart rate during exercise to meet your body’s increased need for blood and oxygen.

Single Chamber Pacemaker

Single chamber pacemaker generally carries electrical impulses from the pulse generator to the right ventricle of the heart.

Dual Chamber Pacemaker

This type of pacemaker carries electrical signals from the pulse generator to the right ventricle and the right atrium of the heart. The impulses aid control the timing of contractions between the two chambers of the heart.

Biventricular pacemaker

It is a treatment option for option with heart failure whose hearts’ electrical systems have been damaged. Unlike a normal pacemaker, a biventricular pacemaker triggers both of the lower chambers of the heart (left and right ventricles) to make the heart beat more efficiently.
A biventricular pacemaker paces both ventricles so that all or most of the ventricular muscle pumps together. This allows your heart to pump blood more effectively. Because this treatment resets the ventricular pumping mechanism, it is called as the cardiac resynchronization therapy.

Risks

Complications from the implantation surgery of the pacemaker are rare, but it could include:

• Infection
• IAllergic Reactions
• ISwelling, bruising or bleeding
• IDamage to your blood vessels
• ICollapsed Lungs

How to prepare

• Electrocardiogram
• Holter monitoring
• Echocardiogram
• Stress test