Transmural contractile reserve after reperfused myocardial infarction in dogs
Key result
Dobutamine challenge recruits inner-layer myofiber shortening and thickening in subendocardial but not transmural infarcts.
- P<0.01
- n=7
Why the study?
The relation between segmental left ventricular function and the transmural extent of myocardial necrosis is complex and crucial for diagnosing myocardial viability with inotropic stimulation.
Does dobutamine stimulation reveal contractile reserve in subendocardial versus transmural experimental infarcts in dogs?
Comparison
Dobutamine stimulation (5 µg/kg/min) vs rest
Design
Experimental preclinical study with tagged magnetic resonance imaging
Follow-up
2 days post-infarction
Authors
Discussion
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Member takes
Implication
Supports experimental viability assessment by infarct layer; leaves open translation to human contractile reserve testing.
Structured PICO
Does dobutamine stimulation reveal contractile reserve in subendocardial versus transmural experimental infarcts in dogs?
P
Population
7 dogs evaluated 2 days after a 90-min closed-chest left anterior descending coronary occlusion followed by reflow.
I
Intervention
Dobutamine stimulation (5 ig x kg(-1) x min(-1))
C
Comparator
Rest
O
Outcome
Transmural left ventricular (LV) function (circumferential shortening, radial thickening, and maximal shortening) assessed by harmonic phase imaging of short-axis tagged magnetic resonance imagessurrogate
Main Result
p-value: p=<0.01
Dobutamine stimulation recruits myofiber shortening and thickening in inner layers of subendocardial infarcts but not transmural infarcts, which may aid in detecting myocardial viability.
Cite This Study
Garot et al. (2000) studied Reperfused myocardial infarction (n=7). Dobutamine stimulation vs. Rest was evaluated on Circumferential shortening (Ecc) and radial thickening (Err) (p=<0.01). Under dobutamine challenge, recruitment of myofiber shortening and thickening was observed in inner layers of segments with subendocardial infarcts, but not in transmural infarcts.