[Dobutamine stress echocardiography in patients with acute myocardial infarct]
V Chaloupka1, L Elbi, S Janousek
1Oddĕlení funkcního vysetrovaání FNsP, Brno-Bohunice.
Insights
Dobutamine echocardiography safely assesses myocardial viability after infarction. Low doses effectively identify viable heart muscle, aiding risk stratification and treatment decisions for patients post-myocardial infarction.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Cardiovascular Medicine
Background:
- Myocardial infarction (MI) poses significant risks, necessitating accurate assessment of cardiac function and viability.
- Early detection of myocardial viability post-MI is crucial for guiding treatment strategies and improving patient outcomes.
Purpose of the Study:
- To evaluate the efficacy and safety of dobutamine echocardiography in patients following a first myocardial infarction.
- To assess the diagnostic performance of low-dose dobutamine echocardiography in identifying viable myocardium.
- To determine the utility of dobutamine echocardiography and maximal stress testing in predicting multi-vessel coronary artery disease and guiding risk stratification.
Main Methods:
- A prospective study involving 39 patients with a first non-complicated myocardial infarction treated with thrombolysis.
- Dobutamine echocardiography performed at rest and with low doses (5 and 10 µg/kg/min) between days 5-7 post-MI.
- Maximal stress testing conducted at two weeks and three months post-MI; coronary angiography performed in 33 patients.
- Assessment of myocardial asynergy, viable segments, and diagnostic accuracy metrics (sensitivity, specificity, predictive values).
Main Results:
- At rest, 237 out of 780 myocardial segments showed asynergy.
- Low-dose dobutamine identified viable myocardium in 87 segments (36%), with sensitivity 72%, specificity 77%, PPV 55%, NPV 88%.
- Dobutamine echocardiography demonstrated high sensitivity (70%) and specificity (95%) for predicting multi-vessel coronary artery disease.
- Improved myocardial kinetics observed at 3 months, particularly in patients undergoing revascularization or rehabilitation.
Conclusions:
- Dobutamine echocardiography is a safe and well-tolerated method for assessing myocardial viability in the early stages after myocardial infarction.
- Low-dose dobutamine echocardiography is a promising tool for differentiating reversible and irreversible myocardial dysfunction.
- Maximal stress testing aids in identifying high-risk patients with multi-vessel disease, informing the need for aggressive treatment strategies.
Abstract:
The objective of the present work was to evaluate dobutamine echocardiography in patients after myocardial infarction. The group of patients comprises 39 subjects, age 54 +/- 10 years with a first non-complicated myocardial infarction treated by thrombolysis. The patients were examined on the 5th-7th day with small amounts of dobutamine (5 and 10 micrograms/kg/min.) and a maximal test after two weeks and three months after the myocardial infarction. During the week after the first maximal test coronarography was made in 33 patients. During the first examination at rest the authors observed asynergy in 237 of 780 segments. Low dobutamine doses revealed the presence of a viable myocardium in 87 segments (36%). The sensitivity, specificity, positive predictive value and negative predictive value were 72%, 77%, 55% and 88%. In eleven patients several arteries were affected, the sensitivity of dobutamine echocardiography for prediction of affection of several vessels was 70% and the specificity 95%. During examinations after three months in some of the patients the kinetics improved, in particular in patients after revascularization operations and in patients who were subjected to a rehabilitation programme. The authors conclude that dobutamine echocardiography is a safe loading method with a minimum of side-effects even in patients in early stages of myocardial infarction. The use of low dobutamine doses is a new promising method for assessment of reversible but also irreversible myocardial dysfunction. The maximal test will help to detect patients with affections of several vessels and help to differentiate patients with a greater risk and necessity of more aggressive treatment.
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