Stress Echocardiography
Stress echocardiography evaluates inducible ischemia by comparing LV wall motion at baseline and during exercise or pharmacologic stress.
Choosing the Stressor¶
- Exercise: preferred when the patient can exercise adequately
- Dobutamine: used when exercise is not feasible
- Vasodilator: less commonly used for wall-motion stress echo
- Low-dose dobutamine: used for low-flow, low-gradient aortic stenosis and myocardial viability
Exercise provides additional information about symptoms, functional capacity, blood-pressure response, and ECG changes.
Acquisition¶
Obtain matched views at baseline and peak stress:
- Parasternal long-axis
- Parasternal short-axis
- Apical four-chamber
- Apical two-chamber
- Apical long-axis
For treadmill studies, acquire post-exercise images as rapidly as possible, ideally within 60–90 seconds. Bicycle exercise permits imaging during stress.
Use an ultrasound-enhancing agent when two or more contiguous LV segments are not adequately visualized.
Interpretation¶
Normal Response¶
- Increased contractility
- Reduced end-systolic cavity size
- Increased LVEF
- No new regional wall-motion abnormality
Ischemia¶
Inducible ischemia produces new or worsening hypokinesis, akinesis, or dyskinesis during stress.
Infarction¶
A fixed wall-motion abnormality present at rest and stress generally reflects scar, although ischemia may coexist.
Viability¶
Improved function with low-dose dobutamine suggests contractile reserve.
A biphasic response—improvement at low dose followed by deterioration at higher dose—strongly supports viable but ischemic myocardium.
Wall-Motion Score¶
| Score | Motion |
|---|---|
| 1 | Normal or hyperkinetic |
| 2 | Hypokinetic |
| 3 | Akinetic |
| 4 | Dyskinetic |
| 5 | Aneurysmal |
A normal WMSI is 1.0. Increasing WMSI indicates worsening regional LV function.
Important Pitfalls¶
- Delayed post-exercise imaging may miss transient ischemia.
- Poor endocardial visualization reduces sensitivity.
- Hypertensive response may produce apparent wall-motion abnormalities.
- LBBB and ventricular pacing can cause abnormal septal motion.
- Prior surgery may alter septal motion.
- Failure to reach an adequate workload reduces sensitivity but does not automatically make the test uninterpretable.
- Ischemia may present as failure of global LV function to augment even without a discrete regional abnormality.
Nonischemic Applications¶
Stress echo may also evaluate:
- Dynamic LVOT obstruction
- Low-flow, low-gradient aortic stenosis
- Mitral stenosis during exertion
- Exercise-induced pulmonary hypertension
- Mitral regurgitation during exercise
- Diastolic reserve in unexplained exertional dyspnea
For low-flow, low-gradient AS, low-dose dobutamine assesses changes in flow, gradient, valve area, and contractile reserve.
Suggested Reporting¶
Exercise stress echocardiography is negative for inducible ischemia at the achieved workload.
New hypokinesis of the ___ segments developed with stress, consistent with inducible ischemia.
Resting akinesis of the ___ segments persists with stress, consistent with prior infarction.
The patient achieved ___ METs and ___% of the age-predicted maximum heart rate. The test was terminated because of ___.
The study is nondiagnostic for ischemia because of inadequate stress and suboptimal visualization of the ___ segments.
Key Points¶
- Exercise is preferred when feasible.
- Acquire peak images quickly after treadmill exercise.
- New or worsening wall-motion abnormality indicates ischemia.
- A biphasic dobutamine response indicates viable, ischemic myocardium.
- Report workload, symptoms, ECG findings, hemodynamic response, and image quality.