Prophylactic versus selective lidocaine for early ventricular arrhythmias of myocardial infarction.

A total of 333 patients arriving within 6 h of the onset of suspected or proven but uncomplicated myocardial infarction were randomized to treatment by either the prophylactic or the selective lidocaine strategy. Patients were monitored for 24 h. The major end points were sustained ventricular tachycardia or fibrillation and emergent adverse effects of lidocaine. There were four episodes of emergent adverse effects of lidocaine, all in patients treated by the prophylactic strategy (2.4%, p = NS). There were two episodes of nonagonal, sustained ventricular tachycardia or fibrillation, both in patients treated by the selective strategy (1.2%, p = NS). The difference between major end points was 1.2% in favor of the selective strategy (p = NS). There were significant differences in lesser ventricular arrhythmias and lesser lidocaine adverse effects but no difference in mortality rate (selective = 3%, prophylactic = 5%, p = NS). Potentially lethal ventricular arrhythmias occurred only in patients with myocardial infarction. Nonlethal but complex ventricular arrhythmias were rare in patients without infarction. However, toxicity occurred in patients with and without infarction. The major conclusion of this study is that there is no important overall advantage of either strategy for lidocaine use in such patients. The advantage of one is the risk of the other. The strategy used should be selected for individual patients, and the use of one strategy for all patients would seem inappropriate.