Implantable Cardioverter Defibrillator (ICD) – a very complicated term that most of you might be hearing for the first time. To know what an ICD is, how is functions, where and why it’s used, you need to brush up your knowledge about the basic function of heart. Heart – as we all know, a small muscular organ that works round the clock to carry out the important task of circulating oxygenated blood to all parts of the body. Your heart acts like a pump that uses electrical signals to rhythmically contract and pump the oxygenated blood all over the body. Sometimes you might notice disorderliness in the rhythm of heart beat resulting in fatal complications like ventricular fibrillation and ventricular tachycardia.
Ventricular fibrillation (VF)
Your heart uses electrical signals to start a heartbeat, it has its own internal electrical system – the pacemaker that controls the rhythm and rate of heart beat. When the heart’s electrical activity becomes disordered, it results in rapid unsynchronized contraction of the lower pumping chambers and as an outcome very little or no oxygenated blood is pumped out of the heart. This condition is termed as ventricular fibrillation. Ventricular fibrillation is a fatal condition that might result in death within minutes, if immediate medical help is not provided.
Ventricular tachycardia (VT)
Ventricular tachycardia is a condition where the heart beats very rapidly than normal. Normal heart beat per minute is termed as pulse rate. The pulse rate varies with age; the normal pulse rate in adults is 70 beats per minute in adults. Your pulse rate varies with different activities like – running, jumping, being excited or frightened, or while having fever. In some abnormal condition like ventricular tachycardia, the pulse rate increases rapidly with a sequence of 3 or more consecutive beats of ventricular origin at a rate greater than 100 beats per minute. As a result, very less oxygenated blood is being pumped out of the heart. Insufficient blood supply decreases the blood pressure leading to unconsciousness.
Implantable Cardioverter-defibrillator
Going back to the term – Implantable Cardioverter-defibrillator (ICD), it is nothing g but a small device that plays an important role in treating the above mentioned fatal conditions. An ICD is a small pager sized electronic device that is surgically placed in your body, either in the chest region or abdomen region that continuously monitors your heart beat and rhythm. When an ICD detects an abnormal heart beat it immediately sends mild electrical impulses to correct the abnormal rhythm.
Ventricular fibrillation and ventricular tachycardia are two very serious life-threatening conditions that cause abnormal heartbeat. Both the conditions if not treated immediately can be fatal. Your doctor will recommend ICD if you fall under one of the following category
- If you have had a ventricular fibrillation
- If you had prior episodes of ventricular tachycardia
- Prior heart attack
- If you had prior episode of sudden cardiac arrest
- If you have hypertrophic cardiomyopathy or
- If your doctor predicts that you are at risk of developing these conditions in the future
An ICD works to continuously monitor your heart rhythm; it immediately identifies an abnormal heart rhythm and sends electric signals to bring it back to normal. Depending on your health condition, your doctor will program your ICD device to take care of one or all of the following functions:
- Defibrillation: A high energy shock wave is sent to the heart when it is beating dangerously fast, to bring it back to normal rhythm
- Anti-tachycardia pacing: When your heart beats really too fast, then the ICD sends mild impulses to the heart muscles to restore back the normal heartbeat and rhythm
- Cardioversion: In order to restore normal heart rhythm, a low energy shock wave is passed to the heart to stop rapid heartbeat
- Bradycardia pacing: This program sends small electrical impulses to activate the heart muscles when it is beating too slowly.
Implantation procedure
Implantation of ICD is done under local anesthesia with a minor surgery, which might take an hour or more depending on the device inserted. Your doctor will program the device according to your heart condition that need to be treated. Programmed ICD is implanted in your collar bone or on the right or left side of your chest or in the abdomen. A small insertion is made and the device is placed under your skin or in the muscles where one end of the lead wire is attached to the vein that goes to your heart and the other end is attached to the generator of the device. After implantation the functioning of the device to treat your condition is monitored by your doctor, for this you might be requested to stay in the hospital for few days. During your regular check-ups make it a point to check the battery life of your generator but anyways it can last for almost 7 years.
After the procedure
Immediately after the procedure your doctor will ask you to limit physical activities until complete recovery. You will be back to normal within a month. In the long run you have to stay away from other high field magnetic or electrical devices that might interfere with your internal ICD. Few devices that you need to keep at bay are – cell phones, MP3 player or iPod, microwave oven, metal detectors, high-tension wires, electrical generators and industrial welders. Disruption of ICD function depends on how long you were exposed to these devices. You will not know even if your ICD is affected therefore if you feel or notice any abnormality contact your doctor immediately. Even medical procedures like Magnetic Resonance Imaging (MRI), shock-wave lithotripsy for kidney stones and Electro-cauterization to stop bleeding during surgery can interfere with you ICD so let your doctor know that you have an ICD implanted.
Feeling after implantation
After implantation, it is normal that you feel uncomfortable for the next 48 hours. Your doctor will prescribe medicines for relieving pain. After implantation when the ICD is performing its task you might feel slight blow in the chest region depending on the therapy it is delivering.
During defibrillation shock, you might feel like being kicked in the chest as it sends the strongest electrical impulse. But relax! it lasts only for few seconds. Anti-tachycardia pacing may not be felt at all. You may feel being punched in chest during a Cardioversion therapy as it uses stronger signals than pacing. During a Bradycardia pacing you might not feel anything as the impulse sent is very mild.
Electrifying your heart!
The benefits of ICD overshadow the risk that it might cause sometime. ICD is very effective in treating grave diseases like Ventricular fibrillation and Ventricular tachycardia. Although an ICD cannot cure heart disease, it for sure lowers the risk of dying by heart disease. However, remember that ICD is only a part of the treatment procedure; it is very important that you take proper medicines, follow healthy diet and visit your doctor regularly and keep a track of your heart.
