Sudden cardiac arrest (SCA) and sudden cardiac death (SCD) occur when the heart abruptly begins to beat in an abnormal or irregular rhythm (arrhythmia).
Without organized electrical activity in the heart muscle, there is no consistent contraction of the ventricles, which results in the heart's inability to generate an adequate cardiac output (forward pumping of blood from heart to rest of the body).
There are many different types of arrhythmias, but the ones most frequently recorded in SCA and SCD are ventricular tachycardia (VT) or ventricular fibrillation (VF).
Less common causes of dysrhythmias in cardiac arrest include pulseless electrical activity (PEA) or asystole.
Such rhythms are seen when there is prolonged cardiac arrest, progression of ventricular fibrillation, or due to efforts such as defibrillation to resuscitate the person.

Sudden cardiac arrest can result from cardiac and non-cardiac causes including the following:
Sudden cardiac arrest (SCA) and sudden cardiac death (SCD) occur when the heart abruptly begins to beat in an abnormal or irregular rhythm (arrhythmia). Without organized electrical activity in the heart muscle, there is no consistent contraction of the ventricles, which results in the heart's inability to generate an adequate cardiac output (forward pumping of blood from heart to rest of the body). There are many different types of arrhythmias, but the ones most frequently recorded in SCA and SCD are ventricular tachycardia (VT) or ventricular fibrillation (VF). Less common causes of dysrhythmias in cardiac arrest include pulseless electrical activity (PEA) or asystole. Such rhythms are seen when there is prolonged cardiac arrest, progression of ventricular fibrillation, or due to efforts such as defibrillation to resuscitate the person.
Sudden cardiac arrest can result from cardiac and non-cardiac causes including the following:
Cardiac arrest