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Despite numerous efforts in recent years, anticipating and preventing sudden cardiac death (SCD) still remains an important “gamble” for modern cardiology. It remains one of the most important causes of death in the industrialised countries. No exact data on the real incidence of cardiac arrest exist, and reported values vary between 0.36–1.28/1000 population per year.1 This variability can be explained by the different methods used to gather data and by the difficulty in classifying sudden death. In the USA an incidence of 1–2/1000 inhabitants per year (0.1–0.2%) has been estimated, with an absolute number of SCD ranging between 300 000–400 000/year.2 Two thirds of these deaths occur out of hospital, and out-of-hospital cardiac arrest accounts for 60–70% of cardiac mortality from all causes. The rhythm observed in victims of out-of-hospital cardiac arrest depends on the time elapsed between collapse and the first ECG recording, and ventricular fibrillation (VF) accounts for 95% of cardiac arrests if this interval is <4 min.3 If the time elapsed is not known, VF represents the first rhythm identified in 40% of the cases, asystole in 40%, electromechanical dissociation in 20% and a ventricular tachycardia (VT) in <1% of the cases.
MAIN CAUSES OF SUDDEN CARDIAC DEATH
In most cases, SCD occurs in patients with structural heart disease. Coronary artery disease (CAD) undoubtedly represents the most frequent cause of cardiac arrest, responsible for 80% of the cases. About 20% of CAD have cardiac arrest as the first clinical manifestation which otherwise can occur during the course of the patient’s clinical history. In particular, patients with a preceding myocardial infarction (MI) represent a category of patients at particularly high risk. At 2.5 year follow up after MI the incidence of arrhythmic mortality was 2%. The most important independent predictive factor for SCD in these patients is left ventricular dysfunction.4 If SCD …