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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.002 |
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 teacher head, 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".