Sudden cardiac death

Sudden cardiac death covers a range of conditions in which there is a cardiac death within one hour of the onset of symptoms, often without previous indication of heart disease. With quick response and aggressive treatment, it is not necessarily fatal, although the survival rate, just as with the television-derived expectation that cardio-pulmonary resuscitation is reliably lifesaving, is dismal. Without aggressive treatment, however, the chances of survival are nonexistent.

It accounts for perhaps half of cardiac deaths, and is most likely due to an abnormal tachycardia leading to ineffective pumping action of the heart.

Risk factors on history
It is a bit confusing to describe the conditions below as "history", because they may not have been symptomatic, and the patient may only be aware of them if he or she is in an aggressive testing program, or if they have produced symptoms.

Familial history is less predictive, but awareness of any of these conditions in a close relative may raise risks
 * Coronary artery disease
 * Dilated cardiomyopathy
 * Hypertrophic cardiomyopathy
 * Valvular disease
 * Long QT syndrome
 * Wolff-Parkinson-White syndrome (WPW)
 * Brugada syndrome
 * arrhythmogenic right ventricular cardiomyopathy