Safety and efficacy of computerized closed-loop delivery of arbutamine: A new pharmacologic myocardial stress modality for the assessment of coronary artery disease

This study evaluated the efficacy of computer-controlled closed-loop delivery of a new synthetic catecholamine, arbutamine, when given to induce myocardial ischemia detected by electrocardiography and echocardiography with a high (10 beats/min/min) and low (6 beats/min/min) rate of increase in heart rate (heart rate slope) in 70 patients with coronary artery disease. The electrocardiographic sensitivity for the detection of myocardial ischemia was 52% for the low slope and 51% for the high slope. The corresponding figures for echocardiographic sensitivity were 83% and 79% for the low and high slopes, respectively. There were no significant differences in changes from baseline to maximum in pharmacodynamic variables, although the mean times to reach maximum heart rate and systolic blood pressure were 1.4 minutes shorter (p=0.001) and 3.7 minutes shorter (p<0.05), respectively, for the high-slope regimen. The duration of the infusion was shorter (p<0.001) for the high slope. In this study, closed-loop arbutamine administration was effective and safe in the detection of coronary artery disease for both heart rate slope regimens.