Impedance cardiography for the assessment of cardiac function during exercise
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Impedance cardiography accurately estimates cardiac function noninvasively. Graded exercise reveals distinct cardiac response phases, with physical training improving cardiac output and workload capacity.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Noninvasive estimation of cardiac parameters is crucial for understanding cardiovascular health.
- Hematocrit correction improves the accuracy of impedance cardiography.
Purpose of the Study:
- To evaluate impedance cardiography for noninvasive cardiac parameter estimation.
- To characterize cardiac responses to graded exercise in different populations.
- To assess the impact of physical training on cardiac function during exercise.
Main Methods:
- Utilized impedance cardiography to measure stroke volume and other cardiac parameters.
- Employed graded bicycle ergometer exercise testing up to maximal load.
- Analyzed changes in stroke volume, cardiac output, ejection index, and atrial wave height.
- Compared responses between healthy subjects and ischemic patients.
Main Results:
- Impedance cardiography provided valuable noninvasive estimates of cardiac parameters when corrected for hematocrit.
- Cardiac response to exercise was characterized by four distinct phases in healthy individuals.
- Ischemic patients exhibited poor exercise tolerance beyond the second phase.
- Physical training led to enhanced cardiac function, evidenced by increased cardiac output and workload.
Conclusions:
- Impedance cardiography is a valuable tool for noninvasive cardiac assessment.
- Graded exercise reveals distinct physiological phases of cardiac adaptation.
- Ischemic heart disease impacts exercise tolerance and cardiac response patterns.
- Physical training positively influences cardiac function during exertion.
Abstract:
1. Impedance cardiography proved valuable to estimate the stroke volume and other cardiac parameters noninvasively, when the electrical resistivity of the blood was corrected with hematocrit. 2. Cardiac response to graded exercise on a bicycle ergometer up to the maximal load in healthy young and active middle-aged subjects was divided into four phases from the changes in cardiac parameters such as stroke volume, cardiac output, ejection index and height of the atrial wave. 3. The ischemic patients did not tolerate well the exercise after the second phase or drift phase of exercise. 4. Physical training enhanced the cardiac function in work through increase in cardiac output and work load.