From the Guidelines
An ICD pacemaker is for patients at risk of life-threatening heart rhythm abnormalities or sudden cardiac death, particularly those with severe heart failure, a history of cardiac arrest, certain genetic heart conditions, or significantly reduced heart function (ejection fraction below 35%) 1.
Key Indications for ICD Therapy
- Severe heart failure
- History of cardiac arrest
- Certain genetic heart conditions like hypertrophic cardiomyopathy
- Significantly reduced heart function (ejection fraction below 35%)
Device Functionality
ICDs can both pace the heart when it beats too slowly and deliver electric shocks to restore normal rhythm when dangerous fast rhythms occur. The device continuously monitors heart rhythm and intervenes automatically when necessary, providing immediate treatment that can be lifesaving 1.
Post-Implantation Care
After implantation, patients need regular follow-up appointments to check device function and battery life, which typically lasts 5-10 years. While ICDs effectively prevent sudden cardiac death, patients should be aware that they may experience occasional shocks, which can be uncomfortable but indicate the device is working properly 1.
Quality of Life Considerations
ICD therapy is generally well tolerated by most patients, but approximately 30% to 50% experience some degree of psychological distress after implantation. The discomfort associated with high-voltage shocks is a principal limitation of ICD therapy, and efforts should be made to minimize unnecessary ventricular pacing to reduce the risk of heart failure 1.
From the Research
ICD Pacemaker Indications
- The implantable cardioverter-defibrillator (ICD) is used to prevent sudden cardiac death (SCD) in patients who have experienced ventricular tachycardia (VT) or ventricular fibrillation (VF) 2, 3, 4, 5.
- ICDs are indicated for primary prevention in patients with ischaemic or non-ischaemic cardiomyopathies, certain congenital heart disease conditions, and inherited channelopathies 2, 5.
- The device is also used in patients who have survived a myocardial infarction and have spontaneous, nonsustained ventricular tachycardia, a low ejection fraction, inducible VT at electrophysiologic study, and whose VT is not suppressed by procainamide 4.
ICD Pacemaker Functionality
- ICDs provide life-saving therapy to prevent sudden cardiac death by delivering an electric shock to the heart when it detects a life-threatening arrhythmia 3, 5.
- The device can also assist with monitoring for heart failure management 3.
- ICDs have evolved to include advanced technologies such as multi-chamber devices, physiologic bradycardic pacing, cardiac resynchronization therapy, atrial and ventricular therapeutic pacing algorithms, and subcutaneous ICDs 5.
Comparison with Other Treatments
- Catheter ablation combined with ICD can reduce ICD therapy, ICD shock, and VT storm in patients with ischemic heart disease, but there is no improvement in all-cause mortality 6.
- ICDs are superior to conventional antiarrhythmic drug therapy in patients who have survived a myocardial infarction and have certain risk factors for SCD 4.