To measure the hearts response to the stress the patient may be connected to an electrocardiogram (ECG); in this case the test is most commonly called a cardiac stress test but is known by other names, such as exercise testing, stress testing treadmills, exercise tolerance test, stress test or stress test ECG. Alternatively a stress test may use an echocardiogram for ultrasonic imaging of the heart (in which case the test is called an echocardiography stress test or stress echo), or a gamma camera to image radioisotopes injected into the bloodstream (called a nuclear stress test). Stress echocardiography
A stress test may be accompanied by echocardiography. The echocardiography is performed both before and after the exercise so that structural differences can be compared. A resting echocardiogram is obtained prior to stress. The images obtained are similar to the ones obtained during a full surface echocardiogram, commonly referred to as transthoracic echocardiogram. The patient is subjected to stress in the form of exercise or chemically (usually dobutamine). After the target heart rate is achieved, stress echocardiogram images are obtained. The two echocardiogram images are then compared to assess for any abnormalities in wall motion of the heart. This is used to detect obstructive coronary artery disease. Cardiopulmonary exercise test
While also measuring breathing gases (e.g. O2, VO2), the test is often referred to as a cardiopulmonary exercise test (CPET). Common indications for a cardiopulmonary exercise test is:
Evaluation of dyspnea. Work up before heart transplantation. Prognosis and risk assessment of heart failure patients.
Unless high-risk markers are present, such as diabetes in patients aged over 40, peripheral arterial disease; or a risk of coronary heart disease greater than 2 percent yearly, most health societies do not recommend the test as a routine procedure.Absolute contraindications to cardiac stress test include:

Acute myocardial infarction within 48 hours
Unstable angina not yet stabilized with medical therapy
Uncontrolled cardiac arrhythmia, which may have significant hemodynamic responses (e.g. ventricular tachycardia)
Severe symptomatic aortic stenosis, aortic dissection, pulmonary embolism, and pericarditis
Multivessel coronary artery diseases that have a high risk of producing an acute myocardial infarction
Decompensated or inadequately controlled congestive heart failure
Uncontrolled hypertension (blood pressure>200/110mm Hg)
Severe pulmonary hypertension
Acute aortic dissection
Acutely ill for any reasonIndications for termination:
A cardiac stress test should be terminated before completion under the following circumstances:Absolute indications for termination include:

Systolic blood pressure decreases by more than 10 mmHg with increase in work rate, or drops below baseline in the same position, with other evidence of ischemia. Increase in nervous system symptoms: Dizziness, ataxia or near syncope
Moderate to severe anginal pain (above 3 on standard 4-point scale)
Signs of poor perfusion, e.g. cyanosis or pallor
Request of the test subject
Technical difficulties (e.g. difficulties in measuring blood pressure or EGC)
ST Segment elevation of more than 1 mm in aVR, V1 or non-Q wave leads
Sustained ventricular tachycardiaRelative indications for termination include:

Systolic blood pressure decreases by more than 10 mmHg with increase in work rate, or drops below baseline in the same position, without other evidence of ischemia. ST or QRS segment changes, e.g.