Advances in Pharmacological Cardiac Stress Testing: Arbutamine Closed-Loop Feedback System

In less than a decade, the use of stress echocardiography has grown dramatically, with both exercise and, for patients unable to exercise adequately, pharmacological stressors, such as dobutamine. A new pharmacological stress agent, arbutamine, administered using a closed-loop computerized feedback system, has recently received approval by the Food and Drug Administration for use with echocardiography and radionuclide myocardial perfusion imaging. This system offers safety and accuracy in echocardiography comparable to the use of dobutamine and promises a number of advantages in terms of ease of use and reductions in personnel and time. A catecholamine specifically designed as a pharmacological stress agent, arbutamine increases heart rate, cardiac contractility, and systolic blood pressure with more balanced chronotropic and inotropic effects than dobutamine. The arbutamine delivery system includes a prefilled syringe of the agent, automatic dosing based on the patient's heart rate response, continuous monitoring of heart rate and blood pressure, a printout of test results, and safety features such as visual and audible warnings and automatic discontinuation of drug after an alarm. The accuracy, safety, convenience, and cost of the arbutamine closed-loop system are likely to make it an attractive agent for echocardiographic diagnosis.