Impact of Spinal Cord Injury and Chronically Induced Orthostatic Hypotension on Left Ventricular Contractility and Stiffness
Bibliographic record
Abstract
Introduction Complete spinal cord injury (SCI) above the T3 spinal level is associated impaired left ventricular (LV) systolic function. However, the effect on diastolic structure and function has yet to be examined. Furthermore, high thoracic SCI impairs centrally‐derived cardiovascular responses to postural change, leading to the development of orthostatic hypotension (OH) post‐SCI. While it has been demonstrated that these frequent bouts of OH cause impairments in cerebrovascular function, it is not known whether this hemodynamic instability also impairs cardiac function. Methods This study examined the effect of SCI on LV systolic and diastolic function in the presence or absence of daily bouts of acutely induced OH. 22 rats were divided into four groups: 1. Rats with a sham injury and no daily OH (SHAM, n=5), 2. Rats with a sham injury and daily induced OH (SHAM‐OH, n=6), 3. Rats with a complete T3 transection injury and daily induced OH (T3‐OH, n=5), 4. Rats with a complete T3 transection and no daily OH (T3‐SCI, n=6). 9 weeks after surgery, LV pressure‐volume (PV) catheterization was performed to assess LV basal PV indices, as well as cardiac contractility and stiffness. Furthermore, the coupling of the arterial system and the left ventricle was characterized to examine the influence of SCI and/or OH on the efficiency of the interaction between the LV and arterial system. Results Compared to both SHAM and SHAM‐OH, the T3‐SCI and T3‐OH groups experienced significant reductions in systolic blood pressure, LV stroke work and cardiac output (all p < 0.023). The T3‐OH group demonstrated an increase in arterial elastance compared to both the SHAM‐OH and SHAM groups (p < 0.014). T3‐SCI and T3‐OH groups exhibited reduced end‐systolic elastance compared to both SHAM and SHAM‐OH (p < 0.04). No difference was found in LV stiffness between the four groups. Finally, the ratio of ventricular‐vascular coupling was found to be significantly increased in the T3‐OH group compared to all other groups (all P< 0.019). Conclusion Complete high thoracic and cervical SCI causes a reduction in LV contractile function. Combined high thoracic SCI and daily OH impairs ventricular‐vascular coupling via changes in arterial compliance. Support or Funding Information Heart and Stroke Foundation of Canada (HSFC), International Collaborations on Repair Discoveries (ICORD), Natural Sciences and Engineering Research Council of Canada (NSERC), Blusson Integrated Cures Partnership (BICP). This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".