For patients who have a very high risk for SCD, an ICD may be inserted as a preventive treatment. An ICD is a small machine similar to a pacemaker that is designed to correct arrhythmias. It detects and then corrects a fast heart rate. The ICD constantly monitors the heart rhythm. When it detects a very fast, abnormal heart rhythm, it delivers energy (a small, but powerful shock) to the heart muscle to cause the heart to beat in a normal rhythm again. The ICD also records the data of each episode, which can be viewed by the doctor when the AICD is interrogated. The ICD may be used in patients who have survived sudden cardiac arrest and need their heart rhythms constantly monitored.

Why is an AICD needed?

Ventricular tachycardia and ventricular fibrillation are two life- threatening heart rhythms that cause the heart to beat very fast. These conditions can be fatal if not treated immediately. Patients receive an AICD because they have had at least one episode of these heart rhythms or are at high risk of developing these types of heart rhythms. Who needs an AICD? An ICD may be recommended for people who: • Had a prior episode of sudden cardiac arrest • Had a prior episode of ventricular fibrillation • Had at least one episode of sustained ventricular tachycardia • Had a prior heart attack and have an increased risk for sudden cardiac arrest or sudden cardiac death • Have hypertrophic cardiomyopathy