Ordinarily, your heart beats at a regular, steady pace called a normal sinus rhythm. It is regulated electrically by the sinus node. However, if certain cells in the lower chamber of your heart (the ventricles) begin to generate their own electrical impulses, these can override the heart’s normal electrical control mechanism. These impulses do not follow the heart’s normal conduction pathway, and may prevent the heart from pumping enough blood and oxygen through the body. One situation, called ventricular tachycardia (VT), may cause you to feel fluttering in the chest or throat or a sensation of dizziness and lightheadedness.
Because less blood is pumped with each beat, your body and brain receive less oxygen-carrying blood, which may result in dizziness, blackouts or fainting, and even unconsciousness. Sometimes VT can be prevented or treated with medications. In other cases, an electrical device is needed to deliver an impulse to the heart to stop the arrhythmia.
When the ventricular arrhythmia becomes even more rapid and unstable, it causes a condition called ventricular fibrillation (VF)-the heart is quivering, and no longer pumps any blood. This leads to cardiac arrest. The only way to correct ventricular fibrillation is to quickly deliver a strong electrical shock to the heart to stop the abnormal rhythm and prompt the heart’s normal electrical conduction system to take over again. This process is called defibrillation.
YOUR IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR
In a hospital or ambulance, when emergencies cause life-threatening arrhythmias, defibrillation is done with an external device called a defibrillator. Paddles are placed against the chest, and a strong electrical impulse is delivered through the heart. However, if your arrhythmia (either ventricular tachycardia or fibrillation) occurs in routine situations, an automatic implantable cardioverter-defibrillator (ICD) can be implanted to monitor and deliver whatever therapy is necessary. It will be programmed to detect and diagnose either ventricular tachycardia or ventricular fibrillation, and will deliver the therapy necessary to correct your abnormal heart rhythms.
Your electrophysiologist may choose to implant a defibrillator in your body to monitor your heart rhythm around the clock and to immediately correct any dangerous arrhythmias should they occur.
The ICD has two components: the generator and the lead(s). The generator is a relatively small, flat, lightweight case that holds a tiny computer and battery. This will generate the electrical impulses used to regulate your heartbeat. The leads are wires covered with soft, flexible plastic. They are connected to the generator and “tell” it how the heart is beating. The leads also transmit the electrical impulses from the generator to the heart.
PREPARATION FOR DEFIBRILLATION IMPLANTATION
We will discuss the procedure — its purpose, benefits, and potential risks — before you receive your ICD. Inserting an ICD is a common, low-risk surgical procedure with a very small risk of complications. These may include: puncture of the heart or lung tissue, damage to the vein, infection, bleeding and/or bruising, or other uncommon events. You’ll be asked to sign a surgical consent form before you have this procedure. If you have any questions or concerns, be sure to call our office.
We will also order a series of tests prior to your ICD. These will include an electrocardiogram (ECG) and some blood tests. We will also go over all medications you’re currently taking and give you any special instructions concerning them
Usually you’ll be instructed not to eat or drink anything after midnight the evening before your procedure. You may, however, take sips of water to swallow pills. If you’re coming to the hospital as an outpatient, you’ll be told where and when to report. You should plan for an overnight stay and arrange for someone to drive you home.
Just prior to the procedure, an intravenous line (IV) will be inserted into your arm to administer any necessary medication, including a sedative to help you relax. The area where the ICD will be inserted will be washed with an antiseptic and shaved, if necessary. Then, you’ll be moved by stretcher or wheelchair to an electrophysiology (EP) laboratory where you’ll be positioned on a special table and covered with sterile drapes. The entire EP staff, who have been trained specifically in the electrical activity of your heart, will be wearing surgical hats and masks to assure that everything remains sterile throughout your procedure.
As the procedure begins, you’ll receive an injection to numb the ICD insertion site. A small incision will be made, and a small “pocket” formed under the skin in your upper chest. Then a lead will be threaded into the vein that runs just below the collarbone. This lead will be guided into your heart using an x-ray monitor.
Once in place, it will be tested to make sure it’s in the best possible position. Then, it will be attached to the ICD generator, which will be placed in the pocket under your skin. At this point, you’ll be given some medication through the IV that will put you to sleep for a few minutes. While you’re asleep, the ICD will be tested to be certain it is functioning properly.
When your EP team is certain your ICD is securely in position and will do its job well, your incision will be sutured (stitched) and covered with a small bandage. Throughout the entire procedure, which takes about 1 1/2 to 2 hours, your ECG, heart rate, blood pressure, and oxygen level will be constantly observed on monitors in the laboratory.
Although you’ll feel some pushing and tugging on your skin at times, there should be little or no discomfort during the procedure. If you feel any discomfort, tell the physician or staff immediately.
After your procedure, you’ll be taken to a hospital room or recovery area. You will be kept overnight in the hospital so that your heart can be monitored to be certain the ICD continues to function properly. You’ll be asked to limit the use of your arm on the side the ICD was inserted. This gives the lead a chance to begin “healing” into your heart.
If you begin to feel some discomfort in the incision area when the local anesthetic wears off, let the staff know and they’ll give you some medication to help make you more comfortable. Be sure to tell your nurse if you experience any unusual symptoms such as hiccups, dizziness, or chest pain.
Make sure you arrange for someone to drive you home when you are discharged. Before you leave the hospital, you’ll be given detailed instructions about caring for the incision site. We will also explain follow-up plans, and discuss what signs and symptoms should be reported.
Your ICD will help protect you against dangerous heart rhythms. However, you also play an important role in staying healthy. Be sure to keep all appointments for exams and follow-up tests. Follow your instructions, don’t hesitate to talk about your concerns.
As always, if you have any questions, be sure to call our office.