· The patient’s heart rate and blood pressure are recorded at rest. Sticky electrodes are attached to the chest and connected to the ECG portion of the Stress test machine.
· The treadmill is then started at a relatively slow "warm-up" speed. The treadmill speed and its slope or inclination is increased every three minutes according to a preprogrammed protocol (Bruce protocol). The protocol dictates the precise speed and slope. Each three minute interval is known as a Stage (Stage 1, Stage 2, Stage 3, etc. Thus a patient completing Stage 3 has exercised for 3 x 3 = 9 minutes). The patient's blood pressure is usually recorded during the second minute of each Stage. However, it may be recorded more frequently if the readings are too high or too low .
· The ECG is constantly displayed on the monitor. It is also recorded on paper at one minute intervals. The physician pays particular attention to the heart rate, blood pressure, changes in the ECG pattern, irregular heart rhythm, and the patient's appearance and symptoms.
· The treadmill is stopped when the patient achieves a target heart rate (this is 85% of the maximal heart rate predicted for the patient's age). However, if the patient is doing extremely well at peak exercise, the treadmill test may be continued further.
· The test may be stopped prior to achievement of the target heart rate if the patient develops significant chest discomfort, shortness of breath, dizziness, unsteady gait, etc., or if the ECG shows alarming changes or serious irregular heartbeats. It may also be stopped if the blood pressure (BP) rises or falls beyond acceptable limits .
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