A submaximal test typically is used for patients undergoing stress testing within 1 week after an acute myocardial infarction. In a submaximal test, the goal is not for the patient to reach his or her maximum tolerated exercise capacity, but to stop at a level lower than that. This goal can be defined as a heart rate of 70% of maximum predicted, a heart rate of 120 bpm, or the completion of a certain stage of a protocol.
1When should an exercise test be stopped?
â¢ Patient desires to stop
â¢ Severe chest pain, dyspnea, dizziness, or other symptoms
â¢ Increasingly severe ventricular ectopy
â¢ New-onset atrial fibrillation or supraventricular tachycardia
â¢ Second- or third-degree heart block
â¢ New bundle branch block
â¢ Severe ST-segment shifts (e.g., 3 mm ST depression)
â¢ Fall in blood pressure below resting level or a 20-mmHg fall in systolic blood pressure
â¢ Systolic blood pressure 300 or diastolic blood pressure 130
What are the risks of exercise testing?
Overall, there is minimal risk associated with performing maximal exercise testing when patients are chosen properly. The frequently quoted risk of serious complication, such as death, myocardial infarction, or life-threatening arrhythmia, is approximately 1 in 10,000 (0.01%).
When is a test considered to have been âœstrongly positiveâ?
A strongly positive test indicates a relatively high likelihood (70%) of severe coronary artery disease being present. Several definitions have been suggested, but most would agree that a test is strongly positive when there is a progressive fall in systolic blood pressure during exercise or when there is evidence for ischemia (angina or significant ST depression) during the first or second stage of the Bruce protocol, especially if exercise is terminated by the patient during one of those stages.