Bruce Protocol (Treadmill Exercise) Test
Formal exercise testing is undertaken when the diagnosis of angina needs to be confirmed in suspected individuals and indeed the severity of the coronary disease.
A standard treadmill or, more rarely, a bicycle ergometer is used and a formal exercise test (ETT) is performed. It is carried out according to a standard protocol.
The patient walks on the treadmill, which has a varying speed (which can be altered, i.e. made faster or slower) and a variable gradient (slope), which can mimic going uphill or upstairs. (The Bruce Protocol is a description of the protocol for the increments in speed and gradient in the treadmill test).
During the time of testing, continual monitoring of the patient’s general condition, ECG and blood pressure take place.
A specialist must supervise and full resuscitation facilities must be available. The patient stops when chest pain or discomfort occurs, or when advised to, by the Specialist.
For the Full (Standard) Bruce Protocol, each stage lasts 3 minutes and the speed and gradient are increased at each stage.
For the modified Bruce Protocol, the gradient, but not the speed, is increased at each stage (see table).
Specific ECG changes indicate myocardial ischaemia.
The modified test is used in cases where standard testing would be too strenuous for the patient. The patient may not be able to participate in exercise testing because of co-existing problems (i.e. severe OA of the hip, or severe chronic obstructive airways disease).
Modified Bruce Protocol
| Stage | Speed (Metres per Min) | Gradient | Duration (Min) | Cumulative Time (Min) | Cum Distance (Metres) |
|---|---|---|---|---|---|
| I | 46 | 0 | 3 | 3 | 138 |
| 2 | 46 | 5 | 3 | 6 | 276 |
| 3 | 46 | 10 | 3 | 9 | 414 |
| 4 | 67 | 12 | 3 | 12 | 615 |
