Due to the continuous development of technology, nowadays there are various cardiac pacemaker systems available for a variety of indications. Pacemaker can be single-chamber, dual-chamber and three-chamber (biventricular):
- Single-chamber pacemakers have one electrode in the right ventricle or rarely in the right atrium
- Dual-chamber pacemakers usually have two electrodes, one in the right atrium and one in the right ventricle
- Three-chamber pacemakers (known as cardiac resynchronization therapy – CRT) typically have one electrode in the right atrium, one in the right ventricle and one additional that stimulates the ventricle (placed in coronary sinus). This type of pacemaker is implanted in patients with impaired heart muscle (which can result in heart failure) to resynchronize the contraction of both ventricles and thereby improve cardiac contractions and consequently blood flow (see: cardiac resynchronization therapy)
Permanent pacemaker implantation. Permanent pacemaker is most commonly implanted in the area below the left collarbone (rarely below the right). Permanent pacemaker’s electrodes are most commonly implanted, through large veins, up to a specific part of the heart muscle and then connected to a pulse generator. The implantation of permanent PM is a surgical procedure performed by a doctor (invasive cardiologist, electrophysiologist or surgeon) under sterile conditions in a laboratory or operating room. The implantation of permanent PM is performed usually under local anaesthesia, or when needed, in deep sedation or rarely general anaesthesia. In the area below the left collarbone, an injection of local anaesthesia is given, followed by a smaller incision (3-5 cm) and formation of a surgical (subdermal) pocket, into which a pulse generator will be placed at the end of the procedure. Through the same incision, one of the larger veins is punctured and one or more electrodes are then introduced under X-ray control. After the electrodes are positioned in a specific heart chamber (atriums, ventricles, or both), their function is tested, and if the function is normal, is connected to the pulse generator and subdermally stored together in a previously formed surgical pocket. The wound is then closed with several sutures and covered sterile gauzes. Implantation lasts approximately 60 minutes.
After implantation of a permanent pacemaker, certain instructions must be followed (see: Instructions for patients when implanting a permanent pacemaker)
Regular check-ups and control. Check-ups after the implantation of permanent PM are usually performed every 6-12 months, depending on the type of PM implanted. At the examination, an ECG is recorded and the pacemaker’s function is tested. If needed, permanent pacemaker can be further adjusted and adapted to the patient’s needs and symptoms.
Permanent pacemaker’s replacement. When the pacemaker battery is depleted, the device’s battery must be replaced. At regular check-ups, the battery shows clear signals of depletion, and patients are then scheduled for shorter hospitalization.
The doctor makes a small incision in the skin over the old scar and removes the old battery, after which the new battery is connected to the existing electrodes and the whole system is than checked for normal functioning. The device is then stored in the same subdermal pocket and closed again with a few stitches. Device electrodes are only changed if something is wrong with them.