Choosing the Right Implantable Cardiac Stimulator

Biotronik ICD

Cardiac stimulators are implanted in certain patients with conditions such as bradycardia, tachycardia, arrhythmia, sudden cardiac arrest, heart failure and atrial fibrillation.

• Bradycardia: is a disease associated with an abnormally slow heartbeat. In this case, a pacemaker is implanted in the patient’s heart. A healthy adult’s heart beats on average between 50 and 80 times per minute. If a patient suffers from bradycardia, their heart beats less than 50 times a minute. This means the heart is unable to pump enough oxygen-rich blood to supply the rest of the body.
• Tachycardia: is a disease associated with an abnormally high heart rate (from 100 beats per minute at rest). The heart is no longer able to efficiently pump blood to the other organs. In this case, an implantable cardioverter defibrillator (ICD) is implanted.
• Arrhythmia: is when the heart has an irregular heartbeat and no longer pumps efficiently. In this case, a cardiac resynchronization therapy (CRT) device is favored.
• Atrial fibrillation: this is the most common form of arrhythmia, in which the atria usually contract too quickly and out of sync. A cardiac resynchronization therapy device combined with a pacemaker (CRT-P) can be used in this case.
• Sudden cardiac arrest: an implantable cardioverter defibrillator (ICD) is favored in this case.
• Heart failure: this is often due to damaged heart muscle that is no longer able to pump effectively. In this case a cardiac resynchronization therapy device combined with a defibrillator(CRT-D) is used.

Vitatron pacemaker

There are three main types of implantable cardiac stimulators: cardiac resynchronization therapy devices (CRTs), pacemakers and implantable cardioverter defibrillators (ICDs).

• Cardiac resynchronization therapy devices (CRTs): A CRT sends weak electrical impulses to the two lower chambers of the heart to help them beat more synchronously. This allows the heart to better pump oxygenated blood to the patient’s body. Two types of devices can be used depending on the patient’s heart failure status:
  • Cardiac resynchronization therapy pacemaker (CRT-P)
  • Cardiac resynchronization therapy defibrillator (CRT-D).
• Pacemakers: A pacemaker sends electrical signals to the heart to increase its frequency, thereby relieving the symptoms of bradycardia
• Implantable cardioverter defibrillators (ICDs): An ICD is used to constantly monitor a patient’s heart rhythm 24 hours a day. If the heartbeat is too fast or irregular, the device sends weak electrical signals to correct it. If, however, the heart rate continues to be too fast, the ICD delivers an electric shock to return the patient’s heart to a normal rhythm.

Medtronic CRT-D

A cardiac stimulator implantation procedure does not require open-heart surgery. The device is implanted subcutaneously in the subclavicular area. Most patients can go home within 48 hours of the procedure. The total duration of the intervention is approximately one hour.

The operation is carried out according to the steps below:

• A local anesthetic, or a general anesthetic if necessary, is administered.
• A 5-10 cm long incision is made in the upper chest, just below the clavicle.
• An incision in a vein (femoral or subclavian vein) allows a lead or leads to be inserted into the heart and connected to the cardiac stimulator.
• The medical device is then programmed and tested and the cardiac stimulator is inserted, usually in the retropectoral position.
• The incisions are then sutured.

The lithium iodide battery in a cardiac stimulator lasts on average between six and eight years and weighs less than 30 g.

Replacing this battery usually requires a new skin incision, made at the site of the old chest incision. Just the battery box is replaced. Because of the high risk of complications from probe removal, the lead or leads are usually used indefinitely unless there are unexpected complications such as infection.

There are risks that may occur during surgery or after the implantation of the stimulator.

• Risks that may occur during surgery:
  • Risks associated with anesthesia
  • Hemorrhaging
  • Damage to adjacent structures (tendons, muscles, nerves)
  • Lung or vein puncture
  • Damage to the heart (perforation or tissue damage)
  • Dangerous arrhythmia
  • Heart attack
  • Formation of a blood clot
  • Stroke
  • Death

• Risks that may occur after the stimulator has been implanted:
  • Infection
  • Skin erosion in the vicinity of the device
  • The device moving from its initial site
  • The lead(s) moving from their original position
  • Irritation of the surrounding tissue, including heart tissue and nerves, due to the electrodes on the leads or the stimulation pulses
  • Device malfunction due to mechanical shock or electromagnetic interference