Prophylactic lidocaine in the prehospital patient with chest pain of suspected cardiac origin.

The prophylactic use of lidocaine in the patient with cardiac chest pain has been reported to reduce the incidence of sudden death from ventricular dysrhythmias in the hospital setting, but few studies have been done in the early prehospital phase. We conducted a randomized, prospective study comparing the effects of lidocaine versus no lidocaine in stable patients presenting with chest pain to a paramedic system. In a one-year period, 446 patients qualified for the study; 222 received lidocaine and 224 did not. The overall hospital mortality of the two groups was 8.1% and 6.7%, respectively (P = .35). Four patients in each group developed sudden death in the prehospital and emergency department settings with ventricular dysrhythmia as the precipitating rhythm. One hundred twenty-nine (29%) had an acute myocardial infarction. The lidocaine and control group contained 68 and 61 of the patients, respectively, with an overall mortality rate of 14.7% and 13.1% (P = .45). The development of significant dysrhythmias (frequent premature ventricular contractions, ventricular tachycardia, bradycardia, second- and third-degree heart blocks) after initiation into the study was similar in both groups of patients. The use of lidocaine was a factor in decreasing systolic blood pressure (P less than 0.03) but did not appear to be clinically significant. For stable patients presenting with chest pain of suspected cardiac origin, prophylactic lidocaine in the prehospital setting was not effective in preventing life-threatening dysrhythmias, but clinically significant side effects were not noted either.