Parachute Left Atrioventricular Valve Causing Stenosis and Regurgitation in a Thoroughbred Foal
Bibliographic record
Abstract
ongenital cardiac abnormalities are rare in the horse.[1][2][3][4] Of reported cardiac anomalies, atrioventricular (AV) valve dysplasia is particularly rare, with the majority of reported cases involving the right AV valve.2,3,5 Left-sided cardiac anomalies in horses causing obstruction to flow are also rare when compared to their frequency in humans, 2 and until recently, none of these lesions were reported to have involved the left AV (mitral) valve.There exists only 1 previous report of left AV valve dysplasia in a foal.4 That foal showed clinical signs as a neonate, was diagnosed through echocardiography, and subsequently died.Hypoplasia of the left AV valve was present at postmortem. 4 True parachute left AV valve is a rare congenital anomaly defined by the presence of a single papillary muscle that receives all chordae tendineae from the left AV valve.[6][7][8][9][10][11][12][13] This condition is most frequently associated with other congenital left heart deformities.[6][7][8][9][10][11][12][13][14][15][16] There are very few reports in the human literature of parachute left AV valve as the sole cardiac deformity.7 In the present report, we describe sole true parachute left AV valvular deformity with absence of the right (subatrial) papillary muscle, diagnosed by echocardiography, in a weaned foal.An 8-month-old Thoroughbred colt was presented to the Ontario Veterinary College Teaching Hospital with a 1month history of ill thrift and exercise intolerance.The colt had been noted to be quiet in comparison to the other weanlings and was stunted.A loud left-sided holosystolic murmur had been auscultated by the referring veterinarian.No previous illnesses had been described in this foal.At presentation, the colt was bright, alert, and responsive with a slightly enlarged abdomen and dense hair coat.Rectal temperature was 101ЊF (38.5ЊC), heart rate 60 beats/min, and respiratory rate mildly high at 36 breaths/min.Mucous membranes were pink and capillary refill time was 2 seconds.Mildly increased lung sounds were auscultated bilaterally.A Grade III-IV/VI holosystolic, low-frequency, coarse murmur was heard on both sides of the thorax, with the point of maximal intensity at the left heart base.Peripheral perfusion was normal.Cardiac rhythm was regular and electrocardiography confirmed normal sinus rhythm.Arterial blood gas analysis revealed normal oxygenation with a partial oxygen pressure of 93.7 mm Hg.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.004 | 0.003 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.008 | 0.004 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".