title: A controlled trial of intramuscular lidocaine in the prevention of premature ventricular contractions associated with acute myocardial infarction.
abstract: Intramuscular lidocaine administration is known to produce blood concentration levels considered to be therapeutic for prevention of premature ventricular contractions. This double blind study was designed to study the effect of intramuscular lidocaine in the prevention of PVC's in acute myocardial infarction. Forty-six patients with confirmed acute myocardial infarction, without congestive heart failure, shock, or major arrhythmias were admitted to the trial. Twenty-one patients received 4.5 mg. per kilogram of intramuscular lidocaine and 25 patients received placebo in the deltoid muscle within 14 hours of the onset of symptoms. Rhythm strips of 2 minutes' duration, blood pressure, heart rate, and blood specimens for blood concentration levels were obtained prior to and 5, 10, 15, 30, 60, 90, and 120 minutes after injection. The mean blood concentration level of lidocaine was 1.81 +/- 0.22 mug per milliliter at 5 minutes, reached a maximum of 2.18 +/- 0.22 mug per milliliter at 10 minutes, and was still 0.81 +/- 0.05 at 120 minutes. Analysis of rhythm strips revealed that only three of 21 patients (14 per cent) in the intramuscular lidocaine group developed at least one PVC as compared to 13 of 25 (52 per cent) in the placebo group (p less than 0.0005). No significant toxic effects were noted. This study suggests that intramuscular lidocaine may significantly reduce potentially fatal arrhythmias in early phases of acute myocardial infarction.
mesh_terms: D000208:Acute Disease; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000517:prevention & control*; D001794:Blood Pressure; D005260:Female; D006352:Heart Ventricles; D006801:Humans; D007273:Injections, Intramuscular; D008012:Lidocaine / Q000008:administration & dosage* / Q000097:blood / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications*
chemical_list: D008012:Lidocaine