The Effects of Intravenous Sildenafil on Hemodynamics and Cardiac Sympathetic Activity in Chronic Human Heart Failure
Bibliographic record
Abstract
BACKGROUND: Erectile dysfunction is common in patients with chronic heart failure and sildenafil is an effective treatment option in this population. Sildenafil has been reported to increase sympathetic outflow in normal volunteers. To date, experience with sildenafil in patients with congestive heart failure is limited and the impact of phosphodiesterase-5 inhibition on sympathetic activity in this population has not been evaluated. METHODS AND RESULTS: 10 patients with heart failure (ejection fraction 23+/-3%) were studied. Generalized and cardiac sympathetic activity responses to an intravenous infusion of sildenafil were measured by the norepinephrine spillover method. In response to sildenafil, there was a significant reduction in mean pulmonary artery (-26+/-5%, P<0.01) and mean arterial pressures (-8+/-1%, P<0.01). These hemodynamic responses were accompanied by a 22+/-5% reduction in cardiac norepinephrine spillover (P<0.02) but no change in total body norepinephrine spillover. CONCLUSIONS: The acute administration of sildenafil is associated with a modest reduction in systemic arterial blood pressure and a more substantial reduction in pulmonary arterial pressure. These hemodynamic changes are observed in the absence of systemic sympathetic activation and are associated with a reduction in cardiac norepinephrine spillover in patients with chronic heart failure. These observations are relevant given the high prevalence of erectile dysfunction in this patient population.
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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".