Stressed? · 14 December 06
Some forms of cardiac disease are easily missed when the patient is at rest, because at rest the patient’s physical examination and ECG are often entirely normal. In these cases, cardiac abnormalities may become apparent only when the heart is asked to perform at increased workloads.
During a stress test the patient is attached to an ECG machine, and a blood pressure cuff is placed on one arm. After a baseline ECG is obtained, the patient begins to perform a low level of exercise by walking on a treadmill. The exercise is “graded” (every three minutes the level of exercise is increased). At each “stage” of exercise, the pulse, blood pressure and ECG are recorded, along with any symptoms the patient may be experiencing.
With a “maximal” stress test (the kind I had), the level of exercise is gradually increased until the patient cannot keep up any longer because of fatigue, or until symptoms (chest pain, shortness of breath, or lightheadedness) prevent further exercise, or until changes on the ECG indicate a cardiac problem (the Cardiologist stopped my test at 5.5 mph, an elevation grade of 16% and a heart rate of 167 bpm, after 13 minutes. A new record for that lab, I was told!).
After the test, the patient remains monitored until any symptoms disappear, and until the pulse, blood pressure and ECG return to baseline. Then a towel is applied to sop up the sweat and the patient is sent home… or back to work, as the case may be.
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