Pacemaker, ICD & CRT Implantation
Pacemakers and implantable cardioverter defibrillators (ICDs) are small devices that deliver energy to the heart through thin, flexible wires called leads. They are implanted beneath the skin, below the collarbone. In the majority of cases we can place the devices with minimally invasive techniques on an outpatient basis (one day or an overnight stay).
The procedure for inserting a pacemaker or ICD is the same.
Pacemakers
Pacemakers work "on demand" to treat slow heart rhythms. The small electronic devices are connected to one or more wires (leads) that run to the heart's atrium and/or ventricle via a vein. When the heartbeat is too slow, the pacemaker delivers a small electrical impulse to stimulate the heart to beat.
The pacemaker is implanted during a procedure in which the patient is under local anesthesia. A vein in the upper chest is opened so the pacemaker wires can be advanced into the heart. The wire must touch the heart to carry electrical signals back and forth between the heart and the pacemaker. The wire is then attached to the pacemaker, which is put in a pouch under the skin.
Pacemaker can also help treat bradycardia, a condition characterized by a slow or irregular heart rhythm, usually fewer than 60 beats per minute.
Implantable Cardioverter Defibrillators (ICDs)
An ICD is an electronic device designed to stop rapid, life-threatening heart rhythms. If the heart has stopped (cardiac arrest) or is experiencing rapid, abnormal rhythms (life-threatening arrhythmias) that cannot be controlled by drugs or other approaches, this device may be used. It may also be used in patients with very weak heart muscle where there is an increased risk of developing dangerous heart rhythms.
The defibrillator uses two approaches to stop rapid, abnormal heart rhythms. The device can stimulate the heart to beat faster than the abnormal rate, which is called overdrive pacing, or it can deliver one or more electrical impulses directly to the heart to stop the rhythm.
The defibrillator is placed in a pocket under the skin of the chest. The device consists of leads and a pulse generator. The leads monitor the heart rhythm and deliver the energy for pacing, cardioversion and/or defibrillation. The generator contains the battery and a tiny computer that processes information to determine the heart's rhythm.
There are three types of ICDs: single, dual chamber and biventricular devices.
• In a single-chamber ICD, a lead is attached to the right ventricle.
• In a dual-chamber ICD, leads are attached to the right atrium and the right ventricle.
• In a biventricular ICD, leads are attached in the right atrium, the right ventricle and the left ventricle. The biventricular ICD is for patients who have had heart failure to provide cardiac resynchronization therapy.
Biventricular Pacemakers or Defibrillators for Cardiac Resynchronization Therapy (CRT)
In addition to conventional pacemakers and ICDs, we use biventricular pacemakers or ICDs for a treatment known as cardiac resynchronization therapy (CRT). CRT devices work by pacing both the left and right ventricles simultaneously, which results in resynchronizing the muscle contractions and improving the efficiency of the weakened heart.
This differs from typical pacemakers, which pace only the right ventricle. CRT seeks to coordinate the heart's contractions and to improve pumping ability and overall heart function.