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Sudden cardiac death (SCD) causes more than 300 000 deaths per annum in Europe, with the same number occurring in the United States, according to current estimations.1,2 This amounts to a death toll of 1–1.5 per 1000 people per year in the industrialised world.w1 In low-income regions of the world, the estimations are less valid. These estimates are based on clinical definitions of “sudden” and “cardiac”. “Sudden” implies that death occurred unexpectedly and that the sequence of events that led to death occurred within a short time span, usually one hour before death. It is generally assumed that the patient was in a stable condition before the sudden and lethal event. “Cardiac” implies that the primary pathology occurred in the heart. This is usually confirmed by the absence of other lethal diseases upon inspection and, whenever available, autopsy. At times, signs of acute myocardial infarction or of acute heart failure can substantiate the assumption of “cardiac” death. Within the limitations of such a definition, it is generally assumed that the majority (85%) of SCD victims die of ventricular tachyarrhythmias, usually in the form of ventricular fibrillation (VF).1 The remaining SCD victims die either of bradyarrhythmias or of acute pump failure.
PRIMARY PREVENTION OF SCD: A DIAGNOSTIC DILEMMA
SCD urgently requires primary prevention because the first clinical event is often fatal, especially in patients with ventricular tachyarrhythmias. Patients with acute bradyarrhythmias often retain a basal circulation—for example, due to ventricular escape rhythms. Thereby, the appropriate treatment (often a pacemaker) can usually be deployed in time to prevent irreversible organ damage when a sudden bradyarrhythmia occurs. VF, in contrast, results in a rapid and complete loss of blood circulation. If left untreated, this condition results in irreversible organ (most notably brain) damage after a few minutes.1 Even in regions of the world with highly …