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Published on: February 10, 2013
Intracoronary Electrocardiography During Dobutamine Stress for Functional Assessment of Myocardial Bridging
Yoshichika Miyazaki1, Ami Kimpara1, Mitsuhito Soh1
1Department of Cardiology, NHO Tokyo Medical Center, Tokyo, Japan.
Insights
Myocardial bridging can cause exertional ischemia. Intracoronary ECG during dobutamine stress testing visualized localized ischemia, aiding diagnosis when surface ECG was normal.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Ischemic Heart Disease
Background:
- Myocardial bridging (MB) can lead to exertional ischemia.
- Assessing localized ischemia from MB is difficult, especially when surface electrocardiography (ECG) is normal.
Background:
Myocardial bridging (MB) can cause exertional ischemia, but functional assessment is challenging when ischemia is localized and undetected by surface electrocardiography (ECG).
Case Summary:
An 83-year-old man with vasospastic angina presented with recurrent exertional chest discomfort. Coronary angiography revealed MB in the mid-left anterior descending artery without significant epicardial stenosis. Intracoronary acetylcholine induced complete occlusion of a diagonal branch with symptom reproduction. Dobutamine stress testing using a pressure-sensor guidewire showed a resting full-cycle ratio ≤0.76 at 20 μg/kg/min, indicating functionally significant ischemia. Surface ECG remained unchanged; however, intracoronary ECG demonstrated marked ST-segment depression distal to the bridged segment, confirming localized ischemia. Switching medical therapy from nifedipine to diltiazem led to symptomatic improvement.
Take-Home Message:
Intracoronary ECG performed during dobutamine stress testing may enable direct visualization of localized myocardial ischemia associated with MB, even in the absence of ischemic changes on surface ECG.
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