NBE Stress Echocardiography 5 — Questions and Answers
Question 1: Which finding during dobutamine stress echocardiography suggests stress-induced cardiomyopathy (Takotsubo)?
- New inferior wall motion abnormality
- Apical ballooning with basal hyperkinesis developing during infusion (Correct answer)
- Isolated septal hypokinesis at peak dose
- Global hypokinesis with preserved apical function
Correct answer: Apical ballooning with basal hyperkinesis developing during infusion
Apical ballooning with compensatory basal hyperkinesis is the hallmark of Takotsubo (stress) cardiomyopathy, which can rarely be triggered by dobutamine infusion.
Question 2: A patient's resting LVEF is 35%. During low-dose dobutamine (10 mcg/kg/min), LVEF increases to 50%. This response most likely indicates:
- Fixed ischemic cardiomyopathy with no viable tissue
- Contractile reserve suggesting hibernating or stunned myocardium (Correct answer)
- Hypertensive response to dobutamine
- Normal response in a patient with dilated cardiomyopathy
Correct answer: Contractile reserve suggesting hibernating or stunned myocardium
An LVEF improvement of ≥5% with low-dose dobutamine indicates contractile reserve, characteristic of viable hibernating myocardium that may improve with revascularization.
Question 3: Which parameter measured during exercise stress echocardiography provides the strongest prognostic information?
- Heart rate at peak exercise
- Peak exercise wall motion score index (WMSI) (Correct answer)
- Resting LV end-diastolic diameter
- Exercise duration on treadmill alone
Correct answer: Peak exercise wall motion score index (WMSI)
Peak exercise WMSI is a powerful independent predictor of cardiac events, with higher scores correlating with worse prognosis and extent of coronary artery disease.
Question 4: During supine bicycle stress echocardiography, images can be acquired during exercise because:
- Heart rate is lower than treadmill exercise
- Patient remains in left lateral decubitus position on the bicycle, allowing continuous imaging (Correct answer)
- The protocol uses lower workloads than treadmill
- Pharmacological agents are combined with bicycle exercise
Correct answer: Patient remains in left lateral decubitus position on the bicycle, allowing continuous imaging
Supine bicycle protocols allow continuous echocardiographic imaging throughout exercise because the patient maintains an imaging-friendly position throughout the test.
Question 5: What is the appropriate action when a patient develops sustained ventricular tachycardia (VT) during dobutamine stress echocardiography?
- Reduce dobutamine dose to 20 mcg/kg/min and continue monitoring
- Administer additional atropine to increase heart rate
- Immediately terminate dobutamine infusion and treat per ACLS protocols (Correct answer)
- Document the finding and complete the remaining protocol stages
Correct answer: Immediately terminate dobutamine infusion and treat per ACLS protocols
Sustained VT is an absolute indication to terminate the dobutamine infusion immediately and manage the arrhythmia according to ACLS protocols.
Question 6: When performing contrast stress echocardiography, what is the PRIMARY reason ultrasound contrast agents (UCAs) are used?
- To measure coronary flow reserve directly
- To improve endocardial border delineation in patients with suboptimal acoustic windows (Correct answer)
- To assess myocardial perfusion only
- To reduce radiation exposure compared to nuclear stress testing
Correct answer: To improve endocardial border delineation in patients with suboptimal acoustic windows
UCAs are primarily used to improve endocardial border delineation in technically challenging patients, enabling accurate wall motion assessment that would otherwise be unreliable.
Question 7: Which echocardiographic criterion defines a positive dobutamine stress echocardiogram for ischemia?
- Any change in heart rate during the infusion
- Development of new or worsening wall motion abnormality in two or more contiguous segments (Correct answer)
- Any increase in LVEF above resting value
- Reduction in LV end-systolic volume by greater than 10%
Correct answer: Development of new or worsening wall motion abnormality in two or more contiguous segments
A positive DSE requires new or worsening wall motion abnormalities in two or more contiguous segments at stress compared to rest, indicating regional ischemia.
NBE Stress Echocardiography 5
Which finding during dobutamine stress echocardiography suggests stress-induced cardiomyopathy (Takotsubo)?