Clinical, electrocardiographic, and biochemical data for immediate risk stratification in acute coronary syndromes.

The recent evolution in therapeutic options for acute coronary syndromes (ACS) mandates early risk stratification in order to select the appropriate treatment strategy for individual patients. Simple clinical data derived from the patient's medical history and physical examination, a standard twelve-lead electrocardiogram (ECG), and determinations of biochemical markers of myocardial damage can be obtained in the emergency room and serve as a guide for deciding appropriate medical management and optimal use of available resources. Even the most important classification of the ACS is based upon a simple and dichotomous description of the ECG, where the presence of ST-segment elevation mandates an immediate attempt to restore coronary perfusion (either pharmacologically or mechanically), whereas its absence suggests pharmacological stabilization before further evaluation. Across the whole spectrum of ACS, clinical history data (such as older age, previous coronary events, and diabetes) and clinical variables (such as higher heart rate, lower blood pressure, and higher Killip class) are the most powerful prognostic determinants at multivariate analyses derived from large databases. The ECG adds significant and independent prognostic information using the analysis of qualitative (direction of ST-segment shift, associated T-wave inversion, and presence of conduction disturbances) and quantitative (number of leads involved, amount of ST- segment shifts, duration of QRS) characteristics. Biochemical markers of myocardial damage have also been identified as independent predictors of events. In addition, retrospective analyses of clinical trials have suggested that biochemical markers might serve as a guide to select pharmacological therapy. However, how to best combine electrocardiographic and biochemical data for immediate risk stratification remains to be further elucidated.