In all patients who experienced a myocardial infarction, an antiplatelet drug will be prescribed, to prevent a new thrombotic event. While different antiplatelet drugs are available to choose from, the cardiologist will weigh the efficacy in preventing thrombotic events to the risk of drug side effects (e.g. risk for bleeding). When a genetic test for a CYP2C19 polymorphism is performed, it is possible to make a more optimal choice between the available antiplatelet drugs, in particular in preventing bleeding events. From a practical point of view, it was shown that the implementation of a genotype-guided treatment strategy for all patients admitted to the hospital for myocardial infarction is feasible.