Sudden Cardiac Death (SCD)
SCD is the largest cause of natural death in the United States causing over 300,000 deaths per year. SCD is responsible for half of all deaths due to heart disease. SCD is a sudden unexpected death caused by sudden loss of heart function. This occurs when the electrical system of the heart malfunctions and causes a fast and irregular heart rhythm (ventricular fibrillation). This results in the ventricles of the heart fluttering or quivering and thus blood is not delivered to the body.
SCD is not the same as a heart attack. A heart attack occurs if blood flow to part of the heart muscle is blocked. Heart attacks, however, can trigger ventricular fibrillation and sudden cardiac arrest because of the sudden lack of oxygen supply to the heart muscle. Following a heart attack scar tissue is formed in the heart. This scar tissue can cause electrical short circuits and can lead to abnormal heart rhythms which can result in SCD.
Other causes of SCD include
*Cardiomyopathy: A cardiomyopathy is a disease of the heart muscle which causes the walls to stretch and enlarge or thicken. In both cases the heart muscle is damaged and this can result in the potential for life threatening arrhythmias.
*Valvular heart disease: Leaking or narrowing of heart valves can lead to damage of the heart muscle. This can result in an increased risk of life threatening arrhythmias.
*Congenital heart disease: SCD can occur in children or adolescents due to a heart condition that was present since birth (congenital heart disease). Adults who have had corrective surgery for congenital heart disease are at increased risk of SCD.
*Some people have a primary abnormality of the electrical system of the heart that can cause SCD. Examples of conditions like these are Long QT Syndrome and Brugada’s Disease. Many of these conditions are caused by genetic abnormalities, and genetic testing is now available for patients and their family members.
The treatment of SCD is the immediate institution of cardio-pulmonary resuscitation (CPR) and defibrillation using electricity to shock the heart back to a normal rhythm. Defibrillation has to be accomplished within 7 minutes or the chance of survival is very slim.
To help achieve the goal of near immediate defibrillation in the community Dr. John Zimmerman and the Department of Electrophysiology at Hackensack University Medical Center created a program to provide all first responders in Bergen County, (police and firefighters), automatic external defibrillators (AEDs) (free of charge) and training in their use. This program has dramatically improved survival from SCD in the community.