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Sensitive method of detecting myocardial ischemia during dobutamine stress echocardiography
Satoshi Yamada1, Taisei Mikami, Kaoru Komuro
1Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan. syamada@med.hokudai.ac.jp
Insights
Dobutamine stress echocardiography reveals that myocardial ischemia causes early-systolic asynchrony in the left ventricular wall. Color kinesis imaging objectively assesses this ischemia during dobutamine stress echocardiography.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Background:
- Coronary artery disease can lead to myocardial ischemia.
- Dobutamine stress echocardiography (DSE) is used to assess cardiac function under stress.
- Early-systolic asynchrony is a potential indicator of myocardial ischemia.
Purpose of the Study:
- To investigate if dobutamine-induced myocardial ischemia causes early-systolic asynchrony in the left ventricular wall.
- To evaluate the utility of color kinesis (CK) imaging in assessing dobutamine-induced ischemia.
Main Methods:
- Color kinesis (CK) images were acquired during dobutamine stress echocardiography (DSE).
- Incremental fractional segmental area change (IFAC) was calculated at 33-ms intervals.
- Ischemic and normal myocardial segments were analyzed in patients with and without coronary artery disease.
Main Results:
- Ischemic segments showed significantly lower IFACs in early systole (0-67 ms) compared to normal segments.
- Later systolic IFACs were significantly higher in ischemic segments.
- The ratio of cumulative fractional area change at 100 ms (peak/low dose) achieved 86% sensitivity and specificity for differentiating groups.
Conclusions:
- Dobutamine-induced myocardial ischemia is characterized by early-systolic asynchrony, not just altered overall wall motion.
- Color kinesis (CK) provides an objective method for assessing ischemia during DSE.
- CK imaging can aid in the diagnosis of coronary artery disease.
Abstract:
To test the hypothesis that dobutamine-induced myocardial ischemia causes early-systolic asynchrony predominantly in the regional left ventricular wall, color kinesis (CK) images during dobutamine stress echocardiography (DSE) were recorded in 13 patients with coronary artery disease and in 10 patients without, all of whom showed normal wall motion at rest. Based on the visual interpretation of DSE and the angiographic findings, 21 segments in the short-axis images at the papillary muscle level were defined as ischemic, and 60 segments of the patients without coronary artery disease were defined as normal. The incremental fractional segmental area change (IFAC) was calculated at 33-ms intervals from the CK images. At the peak dose, IFACs during the first 33 and 33-67 ms were significantly lower in the ischemic segments than in the normal ones, and IFACs during 133-167, 200-233 and 233-267 ms were significantly higher in the ischemic segments. The ratio (peak/low dose) of the cumulative fractional area change at 100 ms gave the best sensitivity (= specificity) for differentiating the 2 groups (86%). Dobutamine-induced ischemia is characterized by an early-systolic asynchrony rather than a change in overall wall excursion and CK can provide an objective assessment of ischemia developing during DSE.