Pacemaker The human heart is an essential organ of the human body. Its sole purpose is to supply the body with oxygen by pumping blood through a complex system of veins and arteries. However, it is often common for the human heart to suffer from various heart conditions, such as a heart block, slow heart beat, heart attack or heart failure. Such heart conditions can lead to weakness, fainting, shortness of breath, or even possibly death. These can usually be treated with medication but in cases where medication is not sufficient, doctors turn to the implantable pacemaker for the solution. The pacemaker is a battery-powered, implantable device, which electronically stimulates the heart to contract and thus pump blood throughout the body.
It consists of three parts, the generator, leads and electrodes. The generator supplies power to the pacemaker via lithium batteries, which typically last 5-10 years. The generator generates the electric impulses that correct the slow heartbeat. Connected to the generator are a series of platinum leads, insulated with a coating of silicone or polyurethane. The leads are responsible for carrying the electric impulses from the generator. Lastly, at the tip of each lead lies a tiny electrode that delivers the necessary electrical impulse to the heart.
There are several types of pacemakers, such as demand pacemakers, fixed-rate pacemakers and rate-responsive pacemakers. Demand pacemakers constantly monitor the patient’s heart rate and only deliver an electric impulse when needed, such as when the heart skips a beat or falls below a programmed minimum. Fixed-rate pacemakers constantly discharge at a regular rate, regardless of the patient’s heart rate. Rate-responsive pacemakers monitor other physical discharges or the body, such as respiration, and change the discharge rate accordingly. The ranges of pacemakers are available to patients to give them a choice of which they would prefer or which would best suit their condition. The pacemaker is not without its limitations.
Patients with pacemakers are advised to avoid devices with powerful electromagnetic fields, as they can reprogram the pacemaker. Such devices include Magnetic Resonance Imaging (MRI) machines, which mean pacemaker patients are unable to take advantage of this new technology. Additionally, pacemaker batteries typically last only 5-10 years, which means when the battery runs low, the patient will have to undergo an operation to change the battery. In this operation the entire generator is replaced with new batteries.
Pacemaker technology is constantly developing. Existing pacemakers have been found to be useful in treating other medical conditions. For example, the pacemaker’s role in correcting slow heartbeats may be effective in the treatment of central sleep apnea. Central sleep apnea is a medical condition in which a patient’s breathing ceases during sleep.
The patient essentially “forgets” to breathe. Pacemakers can improve this condition by setting the pacemaker at a higher resting rate. Furthermore, devices that function as both a pacemaker and a defibrillator are being developed. Such a device would be able to treat both abnormally fast and abnormally slow heart rates..