Peak Exercise and Post‐Exercise Recovery Oxygen Uptake and Muscle Oxygenation in Patients with Heart Failure and Preserved Ejection Fraction and Healthy Matched Adults
Notice bibliographique
Résumé
Background Exercise intolerance and muscle dysfunction characterize heart failure with preserved ejection fraction (HFpEF). Exercise intolerance, as measured by low peak oxygen uptake (VO 2 ), and slow post‐exercise VO 2 recovery are predictors of mortality. The relationship between peak exercise and recovery VO 2 and muscle oxygenation is unknown in this population. Purpose We tested the hypothesis that post‐exercise VO 2 recovery would be slower in patients with HFpEF compared to controls, and that slower post‐exercise VO 2 recovery would be related to slower muscle oxygenation recovery in patients with HFpEF. Methods Eight patients with HFpEF and 8 healthy age‐and sex‐matched controls completed a stationary cycling peak exercise test to volition fatigue followed by 5‐min of passive recovery. Pulmonary VO 2 (gas exchange via metabolic cart) and muscle oxygenation (tissue muscle oxygenation index, TOI) and deoxygenated hemoglobin (HHb via near infrared spectroscopy) were sampled continuously during the exercise test and recovery. Breath‐by‐breath VO 2 data were linearly interpolated to 1‐s intervals, and both VO 2 and NIRS data were averaged into 5‐s time bins. VO 2 recovery data were mono‐exponentially curve‐fitted (OriginPro, 2017) to yield a recovery time constant (tau) and amplitude change. TOI and HHb at end‐exercise, end‐recovery, and the amplitude change were calculated as 10‐s averages. Statistical analyses included independent t ‐tests and stepwise multiple regression. Significance was accepted at P <0.05. Results Peak VO 2 (15.8 ± 5.9 vs. 24.6 ± 6.6 mL/kg/min, P = 0.011) and VO 2 recovery amplitude (−10.0 ± 4.9 vs. −15.1 ± 4.2 mL/kg/min, P = 0.041) were significantly lower in patients with HFpEF compared to matched controls. However, there were no differences between groups in VO 2 recovery tau (98 ± 43 vs. 71 ± 16 s, P = 0.122) nor in any TOI or HHb parameter (all P >0.05). Stepwise regression by group to predict peak VO 2 yielded a positive regression using both peak‐exercise HHb and VO 2 recovery amplitude in HFpEF ( R 2 = 0.957, P <0.001) but only VO 2 recovery amplitude in controls ( R 2 = 0.947, P <0.001). The same parameters predicted VO 2 recovery tau in HFpEF ( R 2 = 0.940, P = 0.001) with no significant finding in controls ( P >0.05). Conclusions Slower post‐exercise VO 2 recovery in patients with HFpEF compared to their healthy counterparts was not confirmed with these data, although this may be largely influenced by the elevated variance in the HFpEF group, or the mild‐moderate HFpEF severity. Regression analyses suggest that the level of muscle deoxygenation, i.e. , the level of O 2 extraction, during peak exercise may be a more important contributor to peak VO 2 in patients with HFpEF compared to their healthy counterparts. The latter may suggest a muscle‐based limitation in HFpEF not observed in healthy controls. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».