If a patient suffers from a slow or a fast heartbeat, there are implantable devices that will make the heartbeat regular and treat an arrhythmia. Slow heartbeats are treated with pacemakers. Fast, dangerous heartbeats, which may lead to cardiac arrest, are treated with implantable cardioverter-defibrillators.
In patients who experience fatigue, dizziness, or fainting with a slow heartbeat, a mechanical generator is necessary to pace the heart to allow normal blood flow. Pacemakers are small computers and are now very small – about the size of two half-dollars placed on top of one another. The generator, which gets placed under the skin by the left or right collar bone, is attached to either one or two small wires that get placed into the vein and into the right side of the heart. Pacemakers are programmed by the physician and the batteries usually last 5-10 years.
A patient who needs a pacemaker will be admitted to the hospital. In the electrophysiology laboratory, under conscious sedation, the pacemaker generator gets placed under the skin. Veins that run underneath both sides of the collar bone are used to access entry to the right side of the heart. The wires are placed in these veins, called subclavian veins. The wires are then attached to the generator and the wound is closed. The incision is about 4 centimeters. The patient stays overnight in the hospital. After a pacemaker is placed, there are virtually no limitations for the patient, other than decreased movement of the arm on the side where the pacemaker was placed for 1-2 weeks. Pacemakers are covered in titanium. This prevents abnormal function from environmental electrical signals. Patients with pacemakers can use household appliances, cellular telephones, and microwave ovens. Only large magnetic field is dangerous for a patient who has a pacemaker. A large magnetic field is only encountered by the patient in the setting of an MRI. CT scans, ultrasounds, and other medical imaging devices are still allowable after implantation of a pacemaker.
An implantable cardioverter-defibrillator is a device that resuscitates the heart – attempts to restore a normal heart beat in a patient whose heart is beating rapidly and in a disorganized way. This is a life-saving therapy and is similar to the machines ambulances bring to patients in the midst of cardiac arrest (no heart blood output). In patients with significant heart disease who are determined to be at risk of sudden cardiac death, implantable cardioverter-defibrillators are placed to shock the heart and resuscitate the patient. An implantable cardioverter-defibrillator is about the size of a Zippo lighter. It gets hooked up to a wire placed in the right side of the heart much like a pacemaker. An implantable cardioverter-defibrillator has the capacity to pace the heart like a pacemaker, but it also has the capability to shock the heart and resuscitate or abort a cardiac arrest. The procedure is performed in the electrophysiology laboratory. Under light sedation, a 5-centimeter incision is made either on the left or the right chest, just below the clavicle. The battery is placed under the skin and a vein located underneath the left or the right clavicle is isolated the wires are placed through that vein to allow entry to the right side of the heart. The wires are attached to the device and the wound is closed. When the patient undergoes implantation of an implantable cardioverter-defibrillator, they also will need testing of the device. Testing of the device requires sedation while the physician puts the patient into their arrhythmia. Under monitored conditions, the device treats the arrhythmia and places the patient back into their normal rhythm. An overnight stay in the hospital is expected for this type of procedure.