Deceived by the Fick principle: blood flow distribution in heart failure.
Eur J Prev Cardiol
; 2024 Jun 27.
Article
em En
| MEDLINE
| ID: mdl-38934631
ABSTRACT
AIMS:
The Fick principle states that oxygen uptake (VÌO2) is cardiac output (Qc)*arterial-venous O2 content difference [ΔC(a-v)O2]. Blood flow distribution is hidden in Fick principle and its relevance during exercise in heart failure (HF) is undefined.To highlight the role of blood flow distribution, we evaluated peak-exercise VÌO2, Qc and ΔC(a-v)O2, before and after HF therapeutic interventions.METHODS:
Symptoms-limited cardiopulmonary exercise tests with Qc measurement (inert-gas-rebreathing) was performed in 234 HF patients before and 6 months after successful exercise training, cardiac-resynchronization therapy or percutaneous-edge-to-edge mitral valve repair.RESULTS:
Considering all tests (n=468) a direct correlation between peakVÌO2 and peakQc (R2=0.47) and workload (R2=0.70) were observed. Patients were grouped according to treatment efficacy in group 1 (peakVÌO2 increase >10%, n=93), group 2 (peakVÌO2 change between 0 and 10%, n=60) and group 3 (reduction in peakVÌO2, n=81). Post-treatment peakVÌO2 changes poorly correlated with peakQc and peakΔC(a-v)O2 changes. Differently, post-procedures peakQc vs. peakΔC(a-v)O2 changes showed a close negative correlation (R2=0.46), becoming stronger grouping patients according to peakVÌO2 improvement (R2=0.64, 0.79 and 0.58 in group 1, 2 and 3, respectively). In 76% of patients peakQc and ΔC(a-v)O2 changes diverged regardless of treatment.CONCLUSION:
The bulk of these data suggests that blood flow distribution plays a pivotal role on peakVÌO2 determination regardless of HF treatment strategies. Accordingly, for assessing HF treatment efficacy on exercise performance the sole peakVÌO2 may be deceptive and the combination of VÌO2, Qc and ΔC(a-v)O2, must be considered.
This study aimed to understand how oxygen uptake during exercise is affected by heart failure therapeutic intervention. We evaluated 234 heart failure patients before and after treatments such as exercise training, cardiac resynchronization therapy, or mitral valve repair, finding that changes in oxygen uptake were poorly correlated with changes in cardiac output and oxygen content difference between arteries and veins. However, we observed a strong negative correlation between changes in cardiac output and oxygen content difference, especially in patients with significant improvement in oxygen uptake. This suggests that blood flow distribution is crucial for oxygen uptake during exercise, regardless of treatment. Therefore, relying solely on oxygen uptake may not accurately assess treatment effectiveness, and considering a combination of oxygen uptake, cardiac output, and oxygen content difference is important. Oxygen uptake during exercise was strongly related to cardiac output and workload.Changes in cardiac output and oxygen content difference were closely related after treatments, especially in patients with significant improvement in oxygen uptake.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Eur J Prev Cardiol
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Itália