The heart is a muscular organ that circulates blood to the entire body by the beating of the heart. The heartbeat is stimulated by an electrical system, which follows a specific pattern and circuit. The electric current causes the heart muscles to contract and expand in a rhythmic fashion, and pump blood to the entire body. When the heart’s electrical system does not function efficiently, it causes abnormal heart beats (either too fast or too slow) called arrhythmias, which can lead to sudden cardiac arrest (heart attack).
A defibrillator is a small device that is surgically implanted to correct an irregular heart rate and rhythm. The defibrillator contains a pulse generator (battery-powered circuit) and one or more electrode leads.
Defibrillators are used to treat conditions such as:
On sensing an irregular heartbeat, the implanted pulse generator sends signals to correct it. Pacing signals correct abnormally fast or slow heartbeats (ventricular bradycardia). If the heart continues to beat very fast, cardioversion or a mild shock is delivered, which feels like a sudden thump in the chest. A stronger shock called defibrillation may be generated by the machine when the heart’s rhythm becomes irregular (ventricular fibrillation). This feels like a punch in the chest. The defibrillator can also monitor your heart’s electrical activity.
The procedure of inserting the defibrillator takes about one to two hours. Your heart rate and breathing are monitored. You are given local anaesthesia to numb the chest area where the insertion is made and you will remain awake for the whole surgery. Your doctor makes a small incision just below your collarbone to create a small "pocket" for the defibrillator.
A sheath (plastic tube) is introduced into the blood vessel and the lead wire of the defibrillator is passed through it into the heart using X-ray video guidance. Once the lead wire is inserted, it is tested for the right location and proper functioning. The pulse generator is then connected to the leads and placed in the "pocket" beneath the collar bone and programmed to treat your heart rhythm. The incision is then closed.
You will remain in the hospital overnight and your heartbeat will be monitored. You might have another X-ray ordered to confirm the position of your defibrillator. You may feel pain or discomfort at the incision site, for which your doctor will prescribe medication. Care should be taken to keep the incision wound clean and dry. You can resume your normal daily routine in a few days. You will be advised to not lift heavy weights and limit movement of the arm close to where the defibrillator is inserted during healing.
Your doctor will give you specific instructions about what to do when you receive several shocks which may include going to the nearest emergency room. Regular follow-ups are very important. Your doctor will check the defibrillator’s batteries, the number of shocks delivered and its proper functioning.
You should avoid strong magnetic fields. You will be given an ID card with all the details of your defibrillator which you will carry with you at all times. This is needed as the device can be detected when you pass through a metal detector at security checks. Keep your cell phone at least 6 inches away from the defibrillator, turn off large motor vehicles when working on them, avoid high-voltage and radar machinery. Always inform your surgeon about the device when you are scheduled for any surgery. You may be refrained from undergoing a magnetic resonance imaging (MRI) procedure, diathermy (heat used in physical therapy for muscle problems) and using a heating pad directly over the device.
Defibrillator insertion may include complications such as: