Non-Invasive Assessment of Cardiodynamics by Impedance Cardiography during the Six-Minute Walk Test in Patients with
Leandro Franzoni1, Rafael Cechet de Oliveira1, Diego Busin2
1Programa de Pós-Graduação em Ciências da Saúde: Cardiologia e Ciências Cardiovasculares ( UFRGS ), Porto Alegre , RS - Brasil.
Insights
Heart failure patients with reduced ejection fraction (HFrEF) exhibit lower cardiac output and heart rate acceleration during exercise compared to healthy individuals. This suggests a potential autonomic response imbalance during submaximal exercise.
Area of Science:
- Cardiology
- Exercise Physiology
- Biomedical Engineering
Background:
- The six-minute walk test (6MWT) is a standard assessment for heart failure (HF) patients, but influenced by various factors.
- Signal-morphology impedance cardiography (SM-ICG) offers non-invasive hemodynamic assessment.
Purpose of the Study:
- To compare cardiac output (CO), heart rate (HR), and stroke volume (SV) responses to the 6MWT in patients with heart failure with reduced ejection fraction (HFrEF) and healthy controls.
- To investigate acceleration and deceleration patterns of hemodynamic parameters during exercise.
Main Methods:
- A cross-sectional observational study design.
- Evaluation of CO, HR, SV, and cardiac index (CI) using SM-ICG before, during, and after the 6MWT.
- Statistical analysis with a significance level of 5%.
Main Results:
- Significant differences in CO and HR acceleration between HFrEF patients and controls (p<0.01 and p=0.039).
- Marked differences in SV, CO, and CI between the groups (p<0.01).
- Impaired SV contribution to CO change in the HFrEF group (22.9% vs. 57.4%).
Conclusions:
- HFrEF patients demonstrated reduced CO and HR acceleration during the 6MWT compared to healthy controls.
- These findings may suggest an autonomic response imbalance during exercise in HFrEF.
- Non-invasive SM-ICG can effectively assess cardiodynamic responses during submaximal exercise in HF.
Background:
Central Illustration: Non-Invasive Assessment of Cardiodynamics by Impedance Cardiography during the Six-Minute Walk Test in Patients with Heart Failure. The six-minute walk test (6MWT) is commonly used to evaluate heart failure (HF) patients. However, several clinical factors can influence the distance walked in the test. Signal-morphology impedance cardiography (SM-ICG) is a useful tool to noninvasively assess hemodynamics.
Objective:
This study aimed to compare cardiac output (CO), heart rate (HR), and stroke volume (SV) acceleration and deceleration responses to 6MWT in individuals with HF and reduced ejection fraction (HFrEF) and healthy controls.
Methods:
This is a cross-sectional observational study. CO, HR, SV and cardiac index (CI) were evaluated before, during, and after the 6MWT assessed by SM-ICG. The level of significance adopted in the statistical analysis was 5%.
Results:
Twenty-seven participants were included (13 HFrEF and 14 healthy controls). CO and HR acceleration significantly differed between groups (p<0.01; p=0.039, respectively). We found significant differences in SV, CO and CI between groups (p<0.01). Linear regression showed an impaired SV contribution to CO change in HFrEF group (22.9% versus 57.4%).
Conclusion:
The main finding of the study was that individuals with HFrEF showed lower CO and HR acceleration values during the submaximal exercise test compared to healthy controls. This may indicate an imbalance in the autonomic response to exercise in this condition.
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