Stress Testing Diagnosis and Tests
Coronary Heart Disease
Most stress tests are done to identify coronary heart disease and assess myocardial viability.
Other Cardiac Diagnostics and Testing
It can also be used for other cardiac conditions, such as
- Valvular heart disease
- Hypertrophic cardiomyopathy
- Dyspnea of cardiac origin
- Pulmonary hypertension
- Mitral valve disease (stenosis and regurgitation)
- Aortic stenosis
- Left ventricular outflow resistance
After the following steps, interpretation can follow.
- The maximal heart rate is determined by the formula of Maximal HR = (208 – age). From that, the target heart rate for the stress test is formulated: 85% of Maximal Heart Rate.
- A 12-Lead ECG is done and BP readings incorporated into the tabulations.
- The test is continued until the patient feels it impossible to continue although a patient’s request to stop before this point, should always be respected. The test is stopped by the provider if there is marked ST depression in the absence of Q waves, ventricular tachycardia, a Mobitz 2 second degree atrioventricular heart block, complete heart block, sustained ventricular tachycardia (or fibrillation), ventricular ectopy, or supraventricular tachyarrhythmia.
- ECG is repeated after 15-30 seconds supine if there the test was done due to a suspicion of ischemia. It is repeated every 2 minutes until the HR falls to < 100 bpm or the ECG returns to the character of the resting ECG.
Shifts in the ST segment, T wave, and the U wave can indicate ischemia:
- ST depression, especially horizontal or down sloping.
- Upsloping ST depression can occur during normal recovery.
- ST segment elevation in association with a resting normal ECG (transmural ischemia and severe multi-vessel coronary artery disease).
As with any ECGs, stress test ECGs can demonstrate bundle branch blocks and other conductive abnormalities.