Age-Related Head-Up-Tilt Test Cardiac-Hemodynamic Profile in Vasovagal Syncope
Bibliographic record
Abstract
To determine the age-related cardio-hemodynamic profile (CHP) during head up tilt test (HUT) in patients with neurally mediated syncope (NMS). 97 subjects (M/F=43/54) with a clinical history of NMS and normal structural heart underwent HUT (70°) 30-minute protocol. 73 patients had positive HUT response (mean time to syncope of 19±7 min) and were included for study analysis. Patients were divided in three study groups for comparison according to age: A = < 30 years (mean age 19±5); B = 31 to 65 years (50±10) and C = >66 years old (77±6). Beat-to-Beat heart rate (HR, bpm), mean blood pressure (MAP) and cardiac impedance were recorded and total peripheral resistance index (TPRI, dyne*s*m2/cm^5) and left ventricular work index (LVWI, mmHg*l/min/m2) were calculated using the Task Force Monitor (CNSystem, AU). Variables were compared at rest, 5 minutes of HUT (ES) and during -2 and -5 minutes prior to the onset of syncope. One-way ANOVA and Student's t test were applied. Variables are shown as means ± SD. Increased baseline HR was found in younger patients (Group A) compared with group B and C (76±15 vs. 67±12, p=0.017; 76±15 vs. 69±11, p=0.076). No statistical differences were found in MAP during HUT comparing groups. TPRI and LVWI are shown in the table as follows Distinct age-related CHP alterations can be documented in patients with NMS provoked by HUT. Younger NMS patients have an increased chronotropic and inotropic activity during rest and OS as well as a decreased vascular reactivity during HUT. Central and peripheral cardiovascular compensatory mechanisms during orthostatic stress may trigger distinct vasovagal responses that vary depending on age.
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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 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".