What are the three types of stress tests?
The three basic types are exercise, pharmacologic vasodilatory, and adrenergic agonist stress tests.
- • Exercise stress tests are typically performed using a treadmill with several possible protocols that sequentially increase the speed and grade of the treadmill. An alternative exercise test uses a stationary bicycle. The goal is to increase heart rate to 85% of the patient’s age-predicted maximum, although others have used a combination of heart rate and blood pressure as a target.
- • Pharmacologic vasodilatory stress tests are performed with adenosine itself, dipyrimadole (an inhibitor of adenosine deaminase that results in increased adenosine within the epicardial coronary arteries), or regadenoson (an A 2A adenosine receptor agonist). Upon injection of these agents, normal coronary arteries will dilate, whereas stenosed arteries will not. The relative discrepancy in myocardial blood flow results in a perfusion defect to the myocardial wall supplied by the stenosed vessel.
- • Adrenergic agonist stress tests are performed using an adrenergic agonist (dobutamine) with which inotropic and chronotropic stimulation results in increased heart rate and contractility simulating exercise.
