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Diastolic indexes during dobutamine stress echocardiography in patients early after myocardial infarction
A Dabrowska-Kugacka1, M J Claeys, F E Rademakers
1Department of Cardiology, University Hospital of Antwerp, Edegem, Belgium.
Insights
Early Doppler parameters during dobutamine stress echocardiography can identify residual ischemia after myocardial infarction. Isovolumic relaxation time (IVRT) changes effectively differentiate patients with and without ongoing ischemia.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Echocardiography
Background:
- Myocardial infarction (MI) poses significant risks, and early detection of residual ischemia is crucial for patient management.
- Dobutamine stress echocardiography (DSE) is a valuable tool for assessing cardiac function under stress.
Purpose of the Study:
- To evaluate the efficacy of Doppler parameters obtained during early-phase dobutamine stress echocardiography (DSE) in distinguishing patients with residual ischemia post-myocardial infarction from those without.
- To identify specific diastolic Doppler indices that can serve as reliable discriminators.
Main Methods:
- Thirty-six patients with recent myocardial infarction underwent DSE, adenosine sestamibi scintigraphy, and coronary angiography within two weeks of the acute event.
- Isovolumic relaxation time (IVRT) and rate-corrected IVRT (IVRTc) were measured at rest and peak dobutamine stress.
- Statistical analysis was performed to compare Doppler parameters between groups with and without residual ischemia.
Main Results:
- The isovolumic relaxation time (IVRT) significantly shortened during dobutamine stress in both groups, but more pronouncedly in patients without residual ischemia.
- At peak dobutamine infusion, IVRT decreased to 54 +/- 11 msec in the control group and 69 +/- 16 msec in the ischemic group (p < 0.01).
- The rate-corrected IVRT (IVRTc) threshold of 80 msec at peak stress demonstrated 80% sensitivity and 70% specificity for detecting residual ischemia.
Conclusions:
- Diastolic Doppler parameters, specifically the isovolumic relaxation time (IVRT) during dobutamine stress echocardiography, can effectively discriminate residual ischemia in the early phase after myocardial infarction.
- Rate-corrected IVRT (IVRTc) offers a quantifiable metric with good diagnostic accuracy for identifying patients requiring further intervention.
Abstract:
The aim of this study was to determine whether Doppler parameters assessed during dobutamine stress echocardiography in the early phase after myocardial infarction could discriminate patients with residual ischemia from those without. Thirty-six patients after a recent myocardial infarction with and without residual ischemia underwent dobutamine stress echocardiography, adenosine sestamibi scintigraphy, and coronary angiography within 2 weeks after the acute event. The only diastolic Doppler parameter discriminating the two groups was the isovolumic relaxation time (IVRT) measured at the peak of the dobutamine infusion. It became shorter in both groups but significantly more in patients without than in those with residual ischemia despite a larger increase in heart rate in the latter group. IVRT at rest was 78 +/- 18 msec and decreased with high-dose dobutamine to 54 +/- 11 msec in the control group and to 69 +/- 16 msec in the ischemic group (p < 0.01). In addition, the rate-corrected IVRT (IVRTc) was calculated: IVRTc = IVRT/sqrtRR. The value of IVRTc = 80 at peak dobutamine infusion is able to discriminate patients with residual ischemia from those without with a sensitivity of 80% and a specificity of 70%.