Sudden cardiac death is defined as an unexpected, non-traumatic death due to cardiac causes within one hour of symptom onset in someone with known or unknown heart disease. Nearly 85% of cases are caused by ventricular fibrillation or ventricular tachycardia. Causes include coronary artery disease, cardiomyopathies, arrhythmias, congenital heart defects, and electrolyte abnormalities. Treatment involves preventing initial and recurrent SCD through medications, implantable cardioverter-defibrillators, and occasionally ablation for rare conditions.

1. ‫الرحیم‬ ‫الرحمن‬ ‫هللا‬ ‫بسم‬

2. Sudden Cardiac Death
(SCD)

3.  Sudden cardiac death (SCD) is defined as an unexpected, non-traumatic death due
to cardiac causes occurring in a short time period (generally within 1 hour of
symptom onset) in a person with known or unknown cardiac disease in whom no
previously diagnosed fatal condition is apparent.
 Nearly 85% of SCDs occur due to ventricular arrhythmias (either primary VF or brief
ventricular tachycardia degenerating to VF).

4. Causes
• Coronary artery disease
• ischemic cardiomyopathy
• Non-ischemic cardiomyopathy
• Hypertrophic cardiomyopathy
• Aortic dissection
• Arrhythmogenic right ventricular
dysplasia
• Arrhythmia from antiarrhythmic agents
• Cocaine
• Myocarditis
• Valvar heart disease (e.g. aortic stenosis)
• Congenital heart disease
• Long QT syndrome
• Brugada syndrome
• Wolff-Parkinson-White syndrome
• Early repolarization syndrome
• Electrolyte abnormalities
• Sarcoidosis
• Amyloidosis
• Cardiac tumors

5. Treatment
 It involves primary prevention (preventing SCD in patients with high-risk conditions),
secondary prevention (preventing SCD in patients revived from SCD) and
cardiopulmonary resuscitation (CPR) in patients presenting cardiac arrest.
 Traditional antiarrhythmic agents have either been ineffective in preventing/reducing
sudden death or have increased sudden death and therefore are not recommended.
 Beta-blockers, ACE inhibitors and spironolactone may be of some benefit.
 Implantable cardiac device (ICD) is the primary treatment modality in most patients.
 Radiofrequency ablation for patients with AV bypass tracts, bundle-branch block-
associated VT, arrhythmogenic right ventricular dysplasia-conditions uncommonly seen.