Use of atropine in patients with recent myocardial infarction during exercise myocardial perfusion study

Abstract

Patients with recent myocardial infarction frequently require a myocardial perfusion study for risk stratification. However a conclusive study cannot be accomplished in many due to non-attainment of target heart rate. To evaluate the effect of pre-stress administration of atropine in exercise performance of patients with recent myocardial infarction. Study included 43 test and 43 control patients and were matched for their age, sex, status of pretest exercise tolerance, area of infarction and for interval between infarction and stress thallium test. Atropine (0.01 mg/kg) was administered intravenously 3 min prior to treadmill stress in all the 43 test patients and no atropine was administered to control patients. Target heart rate was attained in 95.3% patients receiving atropine compared to in 67.4% of control patients. There was no significant difference between mean ages (p>0.33), basal BP (p>0.47), peak BP (p>0.18) of both groups. There was significant difference between the increment in exercise-induced heart rate (p<0.004), peak heart rate (p<0.001) and double product (p<0.001) attained between both groups. No significant adverse effect was noted in patients who received atropine. Pre-stress administration of atropine in patients with recent myocardial infarction is safe and results in a significantly better exercise performance, which might be useful in decreasing the number of equivocal myocardial perfusion studies.