Out-of-Hospital Cardiac Arrest: Getting Beyond the Tip of the Iceberg
Sudden cardiac death (SCD), which is responsible for approximately 300,000 deaths in the United States, refers to an unexpected death from a cardiovascular cause in a person with or without preexisting heart disease. Most studies include cases that are associated with death occurring within 1 hour of an acute change in clinical status, or an unexpected death that occurred within the previous 24 hours1, but this definition is not specific for sudden arrhythmic death. The most common sequence of events leading to arrhythmic SCD is the degeneration of ventricular tachycardia (VT) into ventricular fibrillation (VF), often followed by asystole or pulseless electrical activity (PEA). The transition of "shockable" rhythms (VT/VF) to more ominous rhythms such as asystole or PEA depends on various factors, but is highly dependent on time - the longer the time interval, the more likely the VT/VF will degenerate to PEA or asystole. While VF and VT together represent the initial rhythm in half of all outpatient cardiac arrests, data suggest that with each passing minute of untreated ventricular fibrillation, the likelihood of survival is reduced by 7% to 10%2. (SELECT FULL TEXT TO CONTINUE)
- Received July 13, 2012.
- Accepted July 16, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited