How and Artificial Pacemaker Stimulates a Heart
The pacemaker is essentially the most important part of the heart because its job is to send electrical impulses through the heart causing it to beat. The body’s natural pacemaker is called the sinoatrial (SA) node or the sinus node. If the natural pacemaker is somehow defective, causing irregular heart rhythms, it may be replaced with either a permanent or temporary artificial pacemaker. Artificial pacemakers are battery operated devices that use electrical impulses to stimulate the heart back to a regular rhythm. By placing an electrode on the heart wall, the device can detect all arrhythmia and return it back to normal with artificial electrical impulses.In many human beings their heart does not always respond in the same controlled way to create a normal rhythm. Some conditions that may cause a person to need an artificial pacemaker would be: bradycardia, atrial fibrillation, heart failure, and syncope.
The first pacemaker was invented by Earl Bakken in the 1950’s, at NorthwesternHospital in Minneapolis, Minnesota. A pacemaker is a device that weights approximately one ounce and consist of a programmable chip that controls the flow of impulses sent to the heart in order to control its rhythm. These impulses are delivered by two electrodes attached to the heart muscles; every time it sends a signal to heart, muscles are contracted and the heart beat is produced.
Pacemakers can be single, dual and triple chambered.
Single ChamberThese have one insulated lead to carry impulses to the heart and are either attached to the right atrium or to the right ventricle.
Dual ChamberDual chambered pacemakers have two leads, one to the right atrium and the other to right ventricle; they help the heart to function in a natural way depending on the human body activity.
Triple ChamberThese kinds of pacemakers have two leads, one to the right atrium and right ventricle and the other to the left ventricle. These pacemakers are inserted in patients who have very week heart muscles;hence they help in the contraction of the heart to produce a normal heart beat.
Each of the above mentioned pacemakers are available in three different varieties.
On Demand PacemakersIt monitors the hearts natural electrical activity and discharges impulses whenever the heart beat is slow or it misses a beat.
Fixed Rate PacemakesFixed rate pacemakers discharges impulses at a steady rate regardless of the hearts own beat.
Rate ResponsiveThese are designed to meet the body’s need during its physical activities; it increases and decreases its impulses accordingly.
Reasons for an Artificial Pacemaker In a normally functioning heart the first signal comes from a group of electrically charged cells in the very top of the right atrium, this is known as the body’s natural pacemaker or SA node.The signals then move down through the right and the left atria and across a bridge known as the atrioventricular node or AV node. The signal moving through the right and the left atria causes the first contraction of the heart muscle, this contraction is the smallest of the two because it is not pumping the blood as far as the second contraction will. You will recognize this contraction as the “lub” in the “lub-dub” heart sounds the body makes while pumping blood. As the signal leaves the AV node it moves through the right and left ventricles finally causing the ventricles to contract and force the blood either to the pulmonary arteries or to the aorta to supply the rest of the body with oxygenated blood. This seems like a fairly simple procedure, but in many people’s bodies their heart does not always respond in the same controlled way to create a normal rhythm. Some conditions that may cause a person to need an artificial pacemaker would be: bradycardia, atrial fibrillation, heart failure, and syncope. Bradycardia is a condition where the heart beats to slowly to sustain normal functions; this is very common in elderly people just because their heart has been at work for so long. Atrial fibrillation is when the left and right atria do not contract in a normal way, commonly beating rapidly and with no pattern. Heart failure occurs when the heart is not beating sufficiently or much too slow, this is a big problem because there is a threat of cells being depleted of oxygen which is irreversible (with this condition the brain cells are usually not receiving oxygen which can eventually cause brain damage so severe that the person is essentially brain dead.) Lastly, Syncope is a condition that is usually not as serious and is simply fainting. When fainting occurs, the heart is usually beating very slowly, so in severe cases a pacemaker is used to prevent the person from fainting and return their heart rhythm to normal. An artificial pacemaker is a common treatment for all of these conditions and is very effective in keeping the heart in a normal healthy pattern.
Follow up Needed for Artificial Pacemakers After implantation, routine evaluations are needed to determine if the settings need to be adjusted or modified due to changes in the heart beat. The doctor or technician does not have to directly come in to contact with the pacemaker to do the evaluations. They are not at all invasive and are generally preformed over the telephone with a small machine that the patients are given at the time of implantation. Artificial pacemakers are however, simply technology which means they need some sort of power source. The power used to generate the electrical impulses in artificial pacemakers is from a battery which has a life of approximately 7 years. The procedure to change the battery is minimally invasive and very routine. Any other problems with the pacemaker would be simply to wear and tear; common upkeep on pacemakers is things like replacement leads or a complete replacement of the pacemaker.