The most common electrophysiologic mechanisms leading to SCD are tachyarrhythmias such as ventricular fibrillation (VF) or ventricular tachycardia (VT). Interruption of tachyarrhythmias, using either an automatic external defibrillator (AED) or an implantable cardioverter defibrillator (ICD), has been shown to be an effective treatment for VF and VT. The implantable defibrillator has become the central therapeutic factor in the prevention and treatment of sudden cardiac death.
Patients with tachyarrhythmias, especially VT, carry the best overall prognosis among patients with sudden cardiac arrest (SCA).About 80% of SCD is due to coronary heart disease(CHD). Since this is a condition whose incidence increases with age. SCD is more likely to be due to CHD in older patients. SCD is particularly likely to occur the more severe the CHD, the greater the number of coronary arteries affected and especially where the main trunk of the left coronary artery is obstructed (sometimes called the “widow maker’s disease).