Teaching Patients About Stress Tests and Ambulatory Monitors

The EKG Technician's Scope and Stress Testing Modalities

In cardiac diagnostic testing, clear boundaries define the responsibilities of each healthcare team member. The EKG technician is responsible for educating the patient, preparing the skin, placing leads accurately, and recognizing artifacts during testing. In contrast, diagnosing cardiac conditions and interpreting diagnostic EKG tracings remain solely within the scope of practice of the licensed provider. While technicians do not interpret tracings diagnostically, they must maintain constant vigilance. The technician must immediately alert the provider to life-threatening arrhythmias, severe ST deviations, and critical hemodynamic changes.

An exercise stress test evaluates cardiovascular response by recording the heart's electrical activity, blood pressure, and symptoms during increasing workload. This testing helps the licensed provider evaluate for ischemia and exercise-induced arrhythmias. If myocardial perfusion imaging is needed, an additional imaging test must be performed. The standard Bruce protocol is commonly selected for treadmill testing; it systematically increases the treadmill speed and incline grade every three minutes to raise cardiac workload. For a patient who cannot safely use a treadmill, the provider may select a stationary bicycle if the patient can pedal safely, or choose another appropriate stress-test modality.

When a patient is unable to exercise adequately, or when an exercise test would not yield the required diagnostic information, the provider may order a pharmacologic stress test. Pharmacologic agents challenge the heart using chemical mechanisms. Vasodilating pharmacologic agents, including adenosine, dipyridamole, and regadenoson, work by dilating coronary vessels. Alternatively, dobutamine, a synthetic catecholamine, is administered to increase myocardial contractility and heart rate.

Pharmacologic or exercise stress testing can be paired with diagnostic imaging modalities. Nuclear myocardial perfusion testing uses a radioactive tracer to assess blood flow with stress and, when indicated, at rest. Stress echocardiography compares ultrasound images obtained at rest with images obtained during or immediately after exercise or during pharmacologic stress to assess changes in wall motion.