Sudden cardiac death

Sudden cardiac death (SCD) is defined as follows: "Natural death due to cardiac causes, heralded by abrupt loss of consciousness within one hour of the onset of acute symptoms; preexisting heart disease may have been known to the present, but the time and mode of death are unexpected". The key concepts that are central in the definition of sudden death are the non-traumatic nature of the event and the fact that sudden death is unexpected and instantaneous.

The single most important cause of death in the adult population of the industrialized world is SCD due to ischemic heart disease. In patients with sudden cardiovascular collapse, the most often recorded rhythm shows that ventricular fibrillation is present in 75-80% of cases, whereas bradyarrhythmias are thought to contribute to a minority of SCD. In about 5% to 10% of cases, SCD occurs in the absence of coronary artery disease or congestive heart failure.

Hypertrophic cardiomyopathy is a relatively common cardiac disorder (adult prevalence about 1:500) in which sudden unexpected death is the most devastating outcome, occurring throughout life, but particularly in young, often asymptomatic patients.

Dilated cardiomyopathy is the most common cause of death in dilated cardiomyopaty especially in less advanced functional classes. Ejection fraction has been repeatedly identified as best predictor of outcome both with regards to SCD and death from heart failure; occurrence of syncopal events is another accurate indicator of risk of SCD.

Long QT syndrome is associated with high risk of SCD. Risk stratification is mainly based on history of syncopal events, Torsades de Pointe or cardiac arrest.

Brugada syndrome. Diagnosis of Brugada syndrome is established in the presence of spontaneous or induced ST-segment elevation in leads V¹-V² with/without right bundle branch block.

Aortic stenosis. SCD occurs in about 20 % of patients whose deaths are attributed to aortic stenosis. In the absence of cardiac symptoms, survival is excellent without valve replacement. The prognostic value of different hemodynamic and electrophysiologic testing is limited.

Wolff-Parkinson-White syndrome. In patients with Wolff-Parkinson-White syndrome natural history studies have reported SCD rate of 0,15 % /year due to ventricular fibrillation. SCD survivors tend to be symptomatic.

Bradyarrhithmias. It is estimated that 15-20 % of SCD may be attributed to bradyarrhithmias. Advanced AV block and intraventricular conduction disturbances represent a risk factor for bradyarrhithmic deaths.

Clinical features

Complains: giddiness, darkening in the eyes, sudden appearance of dyspnea.

Objective examination: grave condition, passive position, loss of consciousness expansion of pupils, appearance of pale-grey tint of skin, apnea, absence of heart sounds, absence of pulse on large arteries.

Program examination for the prevention of sudden coronary death:

Clinical examination of patients with IHD, detection of risk factors, reanimated in the acute period of MI with the heart failure; with angina pectoris at rest after the MI; with the complete blockade of bundle-branches block.

Clinical analysis of blood, urinalysis.

Biochemical analysis of blood: total protein, transaminases, creatin-phosphokinase, lactatdehydregenase, cholesterol, triglycerids, coagulogram.

ECG-Holter-monitoring.