Objectives: A pilot study was designed to assess the safety of combined intravenous adenosine and lidocaine in patients with acute myocardial infarction and to estimate the likelihood of a beneficial effect on final infarct size.
Background: Adenosine plus lidocaine reduces infarct size in animals, but the safety and efficacy in human beings is unknown.
Methods and results: Adenosine (70 microg/kg per minute intravenous infusion) plus lidocaine (1 mg/kg intravenous bolus injection and 2 mg/kg per minute infusion) was given to 45 patients with acute myocardial infarction. Patients underwent immediate balloon angioplasty without preceding thrombolytic therapy. Myocardial perfusion defects were measured with serial technetium 99m sestamibi studies. One patient developed persisting hypotension in conjunction with a large inferolateral myocardial infarction. Transient hypotension in three other patients resolved with a reduction in adenosine. Advanced atrioventricular block was never observed. Other adverse events (including atrial fibrillation, ventricular tachyarrhythmia, bradycardia, and respiratory distress) occurred at low frequencies, as expected for patients with acute myocardial infarction. An initial median perfusion defect of 45% of the left ventricle (60% for anterior infarction, 17% for nonanterior infarction) was observed. At hospital discharge (mean +/- SD = 4.3 +/- 2.1 days) the median value was 12%, and at 8 +/- 4 weeks it was 3% (7% for anterior infarction, 0% for nonanterior infarction); 14 patients had no measurable follow-up. Compared with historical control patients, prehospital discharge measurements were not different but late perfusion defects were improved.
Conclusions: Treatment with intravenous adenosine and lidocaine during acute myocardial infarction has sufficient safety and potential for improved myocardial salvage. Randomized studies are justified.