Yes. Normally during exercise, there is a widening of the pulse pressure caused by a gradual rise in systolic pressure and a slight fall or no change in diastolic pressure. Failure of the systolic pressure to rise at least 30 mmHg is considered abnormal and may be related to heart failure and/or severe ischemia (occasionally, these conditions may even cause a fall in systolic pressure). Antianginal or antihypertensive medications (e.g., beta blockers or calcium channel blockers) usually cause a mild blunting of the rise in systolic blood pressure. A rise in systolic pressure significantly above 200 mmHg is considered a hypertensive response to exercise.
How is an individual’s expected maximum heart rate determined?
The maximum predicted heart rate (MPHR) varies among individuals but is reasonably well predicted by the formula MPHR = 220 – age.
Can anything be learned from the exercise heart rate response?
Mainly, the heart rate is considered an index of the intensity of exercise. In general, the closer a patient gets to his or her predicted maximum heart rate, the more intense the exercise is, the more stress is placed on the cardiopulmonary system, and the more sensitive the test will be for detecting an abnormal condition. By convention, most clinicians accept a heart rate of 85% of predicted maximum as reflective of near-maximal exerciseâ”a level of exercise that yields a sufficiently sensitive test.
A rapidly rising heart rate at low levels of exercise can indicate severe deconditioning and/or severe cardiopulmonary disease. Rarely, severe cardiac disease can cause an inadequate heart response to exercise. This is referred to as chronotropic incompetence.
List four factors that interfere with the ability to interpret an exercise ECG.
Even in the absence of an interpretable exercise ECG, the exercise test can still yield useful information about exercise capacity, presence or absence of symptoms or arrhythmias, and the patient’s heart rate and blood pressure response to exercise.
What does it mean when a patient gets chest pain during an exercise test?
Chest discomfort is fairly common and often nonspecific during exercise testing. However, the symptoms must be assessed in an attempt to decide how closely they match the classic description of angina. Chest discomfort is classified into one of three categories: clearly cardiac, clearly noncardiac, or uncertain. Obviously, chest discomfort in the first two categories helps with interpretation of the test, whereas discomfort in the latter category leaves the clinician uncertain.
Overall, the presence of exercise chest pain makes the likelihood of obstructive coronary disease greater, but absence of chest pain does not rule it out. Asymptomatic ischemia with exercise may be more likely in patients with diabetes.
1List the absolute contraindications to maximum exercise testing.