An artificial pacemaker is a small battery-operated device that helps the heart beat in a regular fashion. It evaluates the heart’s electrical system and when necessary, sends electrical signals at regular intervals to the heart to rectify abnormalities in the heart’s electrical system.
The Sinoatrial node, which is the heart’s natural pacemaker, emits a steady burst of electrical signals comprised of electrically active cells. The signals then travel to the electrical bridge (the Atrio-Ventricular node) between the upper and lower chambers and finally, move to the lower chambers. A problem in the electrical pathway can disrupt the heart’s regular beating, artificial pacemakers help rectify these issues.
The artificial pacemaker has two parts: a generator and wires (leads).
The generator is a small unit powered by a battery, it produces electrical impulses to stimulate the heart to beat. The generator is implanted under the skin and is connected to the heart with the help of tiny wires, the impulses flow at regular intervals through these wires, just like how the impulses from the heart's natural pacemaker would flow. Today, the battery in artificial pacemakers last for about 8-12 years.
The pacemaker leads identify the heart’s own electrical activity and transmit the information to the pacemaker generator. If the heart rate is too slow, the generator diffuses tiny electrical signals to the heart to stimulate the contraction of the heart muscle. Thus, pacemakers do not replace the working of the heart; the heart still beats on its own, the pacemaker merely helps regulate the timing of the heartbeat.
Some pacemakers are used externally and temporarily, and not surgically implanted.
Pacemakers are implanted in the body through a minimally invasive surgery, it is done with the help of local anaesthesia, and generally takes less than an hour.
A small incision is made under the patient's collarbone and a “pocket” is created under the skin in the tissue covering the muscle. The pacemaker leads are then inserted through a vein near the site of the pocket and is pushed into the heart with the help of fluoroscopy (X-Rays). The leads are attached to the generator that is placed in the pocket, and the incision is closed.
In about 2 to 4 weeks, the patient can return to a completely normal routine.
Pacemaker generators are in essence, tiny computers and the software is “tweaked” to suit individual users. Pacemakers can be programmed with a handheld device non-invasively since the external device communicates with the pacemaker through the skin. The programming can be repeated or altered as necessary depending on the patient’s heart rhythm changes.
It is important to check the implanted pacemaker periodically to ensure effective functioning and battery efficiency. An elective pacemaker replacement is done when the battery begins to get low. No batteries are changed; instead, the old generator is replaced with a new one and the pacemaker leads need not be replaced. This is not merely a "battery change" although some doctors sometimes use the term.