Diseases that are associated with sudden cardiac death were identified in 0.38% of adolescent soccer players in a cohort that underwent cardiovascular screening. The incidence of sudden cardiac death was 1 per 14,794 person-years, or 6.8 per 100,000 athletes; most of these deaths were due to cardiomyopathies that had not been detected on screening. (Funded by the English Football Association and others.).
The term acute coronary syndrome refers to a range of acute myocardial ischaemic states. It encompasses unstable angina, non-ST segment elevation myocardial infarction (ST segment elevation generally absent), and ST segment elevation infarction (persistent ST segment elevation usually present). This article will focus on the role of percutaneous coronary intervention in the management of unstable angina and non-ST segment elevation myocardial infarction; the next article will address the role of percutaneous intervention in ST segment elevation infarction.Although there is no universally accepted definition of unstable angina, it has been described as a clinical syndrome between stable angina and acute myocardial infarction. This broad definition encompasses many patients presenting with varying histories and reflects the complex pathophysiological mechanisms operating at different times and with different outcomes. Three main presentations have been describedangina at rest, new onset angina, and increasing angina.
PathogenesisThe process central to the initiation of an acute coronary syndrome is disruption of an atheromatous plaque. Fissuring or rupture of these plaques-and consequent exposure of core constituents such as lipid, smooth muscle, and foam cells-leads to the local generation of thrombin and deposition of fibrin. This in turn promotes platelet aggregation and adhesion and the formation of intracoronary thrombus.Unstable angina and non-ST segment elevation myocardial infarction are generally associated with white, platelet-rich, and only partially occlusive thrombus. Microthrombi can detach and embolise downstream, causing myocardial ischaemia and infarction. In contrast, ST segment elevation (or Q wave) myocardial infarction has red, fibrin-rich, and more stable occlusive thrombus.
475 patients with suspected uncomplicated myocardial infarction (MI) were divided into 3 groups based on their entry ECG: group 1--significant ST elevation; group 2a--ST depression or T inversion; group 2b--normal ECG. Infarction was confirmed in 99.7% of group 1, 68.5% of group 2a and 39.7% of group 2b patients. Despite similar clinical, haemodynamic and historical variables at presentation, group 1 patients had significantly larger MI, more in-hospital complications and a higher short-term and long-term mortality (P less than 0.005) than group 2 patients. The entry ECG of patients with suspected MI is an excellent and simple predictor of those who are most likely to have an MI confirmed and identifies a group of patients at high risk of death or developing complications.
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