Prediction and Prevention in Sudden Cardiac Death

Despite the significant decline in coronary artery disease (CAD) mortality in the second half of the 20th century, sudden cardiac death (SCD) is the most common cause of death worldwide, accounting for more than 50% of all deaths from cardiovascular disease 1-4. The condition is characterized by an unexpected cardiovascular collapse due to an underlying cardiac cause 5. The International Classification of Diseases, Tenth Revision, defines sudden cardiac death (SCD) as death due to any cardiac disease that occurs out of hospital, in an emergency department, or in an individual reported dead on arrival at a hospital. In addition, death must have occurred within 1 hour after the onset of symptoms 6. The underlying cause may be a ventricular tachycardia (VT), ventricular fibrillation (VF), asystole, or nonarrhythmic causes 7. Sudden cardiac death (SCD) continues to claim 250000 to 300000 US lives annually 8. In North America and Europe the annual incidence of SCD ranges between 50 to 100 per 100000 in the general population 9-13. Because of the absence of emergency medical response systems in most world regions, worldwide estimates are currently not available 14. In urban India the trend of SCD is similar to the West 15. SCD represents a major challenge for the clinician because most episodes occur in individuals without previously known cardiac disease 1-4. Even with the best first responder systems the average survival is approximately 5% 16. On average, only 8% of those receiving community-based resuscitation are discharged from the hospital alive 2. The discovery of effective prediction & prevention modalities, therefore, is of great importance.