Does Dobutamine Improve Ventricular Function in Dogs with Regional Myocardial Dysfunction?
Bibliographic record
Abstract
UNLABELLED: We studied the effect of systemic dobutamine infusion (4 microg. kg(-1). min(-1) IV) on regional wall motion abnormalities (RWMAs) in eight anesthetized open-chested dogs. We hypothesized that infusion of small doses of dobutamine would reduce RWMAs and improve global ventricular function. Apical RWMAs were induced by local intracoronary boluses of 9.0 mg esmolol. Phase angles, effective stroke volume (SV), maximum SV, stroke work, and segmental shortening were compared among four left ventricular (LV) regions (apical, papillary, chordal, and basal) during baseline, dobutamine, esmolol, and dobutamine-esmolol treatments. The minimal global LV volume was designated as 0 degrees, and the cardiac cycle was divided into 360 intervals. Regional phase angles were defined as the distance (in degrees) that regional minimum volume differed from global minimal LV volume (end-systole). RWMA decreased blood pressure (92 +/- 2 mm Hg to 84 +/- 3 mm Hg) and increased LV end-diastolic pressure (1.8 +/- 0.5 mm Hg to 4.2 +/- 0.8 mm Hg). RWMA delayed regional contraction (-2.9 degrees +/- 1.6 degrees to 52.3 degrees +/- 1.5 degrees ) and decreased effective SV (2.3 +/- 0.4 mL to 1.6 +/- 0.3 mL) in the affected apical region but did not decrease maximal SV. Systemic infusion of dobutamine restored global LV function but failed to eliminate RWMA, as evidenced by decreased apical synchrony, effective SV, and stroke work. We concluded that systemic dobutamine restored global LV function but failed to correct RWMA. IMPLICATIONS: We examined the effect of systemic dobutamine on regional wall motion abnormalities (RWMAs) induced by intracoronary esmolol infusion in eight anesthetized dogs. Esmolol dilated the heart and decreased regional synchrony of contraction. Dobutamine restored cardiac function but failed to correct the asynchrony of regional contraction caused by esmolol-induced RWMAs.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".