A modified treadmill exercise protocol for computer-assisted analysis of the ST segment/heart rate slope: methods and...

Area of Science:

• Cardiology
• Exercise Physiology
• Diagnostic Testing

Background:

• The standard Bruce protocol is widely used for exercise stress testing.
• ST segment/heart rate slope is a valuable metric in assessing cardiac function during exercise.
• Limitations exist in the Bruce protocol's heart rate increments, potentially affecting accuracy.

Purpose of the Study:

• To introduce and evaluate a modified treadmill exercise protocol.
• To improve the accuracy and applicability of the ST segment/heart rate slope.
• To reduce heart rate increments between exercise stages compared to the Bruce protocol.

Main Methods:

• A modified treadmill exercise protocol was developed with smaller heart rate increments.
• 150 patients were exercised using the new protocol, and 150 using the standard Bruce protocol.
• ST segment depression accuracy was validated against physician measurements in angina patients.

Main Results:

• The new protocol achieved similar exercise tolerance and physiological responses (heart rate, blood pressure) as the Bruce protocol.
• Mean heart rate increment per stage was significantly lower (10 beats/min) in the new protocol versus the Bruce protocol (27 beats/min).
• Serial testing showed superior reproducibility for the ST segment/heart rate slope compared to other exercise parameters.

Conclusions:

• The modified treadmill protocol is a viable alternative to the Bruce protocol.
• Reduced heart rate increments enhance the accuracy and reproducibility of the ST segment/heart rate slope.
• This improved metric aids in more precise cardiac assessment during exercise stress tests.