An ICD or Implantable Cardioverter Defibrillator is an incredibly important device for those at risk of cardiac arrest and sudden cardiac death. Certain arrhythmias are more immediately dangerous than others and can cause the heart to stop beating. If this is the case, external defibrillators, often found in public places, must be deployed almost immediately to save the patient’s life. Even a delay of a few minutes may be enough for a patient to pass away. Of course, anyone who lives with the risk of sudden cardiac death and doesn’t have immediate access to an external defibrillator puts themselves at risk each day. Further, many patients curtail their lifestyle, not performing activities that they otherwise would, out of fear.
For these patients, an ICD is usually an excellent option. An ICD is much like a pacemaker in that it monitors the heart’s beats (some ICDs also serve as pacemakers). However, ICDs offer the added feature of shocking the heart back into rhythm if it senses a critical failure. Much like using an external defibrillator, the small device mitigates the risk of sudden cardiac death, but automatically, and from within.
How the device is implanted
ICDs are implanted in a very similar fashion to a pacemaker. The pulse generator is implanted under the skin near the collarbone and one or more leads are affixed to the heart directly via a vein to the heart.
S-ICDs, or subcutaneous ICDs, are used when there is a structural defect of the heart that precludes using a traditional ICD. The pulse generator is usually implanted on the side of the chest and the lead runs around the breastbone and into the heart. While the S-ICD is generally less invasive than the traditional ICD, it is also significantly larger.
ICD implantation is usually performed in a surgery center or hospital setting, and most patients go home on the same day. Recovery is relatively swift, but most patients are discouraged from performing strenuous activities for about 4-to-6 weeks after the procedure.
Over time, the ICD may deliver one or both of two forms of electric shock. A mild electric shock that is used for pacing the heart may simply feel like a slight flutter. This low-energy pacing responds to less-severe disruptions in the heart rhythm. High-energy shocks are delivered when the rhythm issue is more severe. The shock can be painful, but patients return to normal within seconds.
A single high-energy shock is usually enough to get the heart back to normal pacing, but if more than two shocks occur during any given 24-hour period, this may be a sign of either a device failure or of a serious issue with the heart. Patients should visit the emergency room immediately in this case.
Benefits and risks of an implantable cardiac defibrillator
ICDs offer an exceptional benefit for anyone who requires them. They are truly lifesaving in many cases, and secondarily provide peace of mind to those who would otherwise be concerned about cardiac arrest. However, as with any device, there are risks:
- Generally associated with any medical device is the risk of pain, blood loss and infection at the implantation site. While the procedure is minor, it still comes with some risk, which is often easily managed by an experienced Electrophysiologist.
- ICDs also have the possibility of firing inappropriately and when no heart failure is present. This, of course, gives the patient a severe shock which can be off-putting and anxiety inducing. Fortunately, technology has improved to where these false positives have been minimized.
- As with any battery-operated medical device, the pulse generator has a limited lifespan, and patients may require replacement after some time.
The Bottom Line
If a heart defect or cardiovascular disease has increased the risk of cardiac arrest or sudden cardiac death, it is important that you speak to a qualified electrophysiologist to learn more about ICDs and how they could save your life. We encourage you to schedule an appointment with one of our electrophysiologists to learn more.