If your heart isn’t beating at the right rate or rhythm, doctors have several options to help you.
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Pacemakers and defibrillators take over pacing your heartbeat when heart disease and other conditions play havoc with heart rhythms.
Your heart signals
Normally, electrical impulses generated in your heart stimulate the heart to contract. This moves blood through the heart, to the lungs, allowing oxygenated blood back in, and then forcefully pumps it out to your body and brain.
If the electrical impulses are interrupted for any reason, the heart rate can go too slowly and that may make a pacemaker necessary. If the electrical impulses disorganize, the heart may go too rapidly and require an implantable defibrillator.
Bruce Wilkoff, MD, Director of Cardiac Pacing and Tachyarrhythmia Devices, answers important questions about pacemakers and defibrillators (ICD):
What are pacemakers and what do they do?
Pacemakers are implantable devices that consist of:
- A battery-operated control unit (pulse generator) usually implanted under the skin in the chest area.
- Lead wire(s)that are threaded to the chambers of your heart and attached to the heart muscle that detect the heart rate and deliver small pulses of energy from the pulse generator to the heart.
Pacemakers can help:
- Prevent heart rhythms from going too slowly.
- Coordinate the heart beats so that the top and bottom and left and right chambers beat synchronously. This may help some people with advanced heart failure.
Why are there different types of pacemakers and different numbers of lead wires?
There are three basic kinds of pacemakers:
- Single chamber. One lead attaches to the upper or lower heart chamber. Used in specific rhythm disorders. A leadless pacemaker is a new technology that is being researched to treat slow heart rhythms without a lead.
- Dual chamber. Two leads are used, one for the upper and one for the lower chamber.
- Biventricular pacemakers (used in cardiac resynchronization therapy). These use leads attached to three places – the top chamber, and both lower chambers (right and left ventricles).
Dr. Wilkoff says, “Pacemakers are designed to keep your heart from going too slowly and this helps your heart to pump more blood to your body. Defibrillators rescue the heart from a rapid and confused heart rhythm which is usually fatal. Some people need help with both problems.”
What is a defibrillator and what does it do?
Implantable cardioverter defibrillators (ICDs) are devices that send a strong “reset” signal to your heart when the bottom chambers of your heart (ventricles) are beating very fast or erratically. These ventricular arrhythmias can occur without warning and are often fatal.
Almost 95% of all people who experience cardiac arrest die before ever reaching a hospital.
Defibrillators can help:
- Save the lives of patients who have fast ventricular arrhythmias.
- Patients who have significant damage to their hearts after heart attacks or poor heart muscle function due to cardiomyopathy. These patients are at greater risk for dangerous ventricular arrhythmias and benefit from ICD implantation.
Do some patients need both a defibrillator and a pacemaker?
Yes. Some patients receive a combination pacemaker and defibrillator. For patients with heart failure, a combination biventricular-defibrillator device helps the heart to pump blood more forcefully. It also protects the patient against potentially fatal arrhythmias. For others, the defibrillator protects against life threatening arrhythmias and the pacemaker backs up the heart rate if it gets too slow.
Are pacemakers and defibrillators just for old people?
No. Dangerous rhythm disorders can affect young people too. When athletes collapse on the field after practice, the culprit often is some form of heart rhythm abnormality.
In both cases, the defibrillator can detect when the heart starts to quiver or beat erratically and reset it, saving the patient’s life.
In order to determine what type of device is appropriate for you, your cardiologist will order tests to determine what type of rhythm disorder you have and if you need treatment.