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[Myocardial metabolism during dynamic exercise]
K Sato1, Y Nishinaka, Y Morishita
1Department of Clinical Laboratory, Nagoya University Hospital.
Rinsho Byori. the Japanese Journal of Clinical Pathology
|September 1, 1993
Summary
Exercise impacts myocardial substrate uptake in ischemic heart disease patients. While uptake rates for glutamate and fatty acids decrease, overall myocardial uptake of glutamate, glucose, and lactate increases, indicating altered cardiac metabolism.
Area of Science:
- Cardiology
- Biochemistry
- Exercise Physiology
Context:
- Coronary sinus blood flow measurement is crucial for understanding myocardial substrate uptake kinetics.
- Ischemic heart disease (IHD) affects myocardial metabolism and substrate utilization.
- Exercise challenges cardiac function and alters substrate demand.
Purpose:
- To evaluate exercise-induced hemodynamic alterations in patients with ischemic heart disease.
- To examine changes in myocardial substrate uptake kinetics (uptake rate and uptake) during exercise.
- To determine the relationship between myocardial glutamate uptake and hemodynamic changes.
Summary:
- Eighteen IHD patients underwent exercise testing, measuring coronary sinus blood flow and myocardial substrate uptake.
- Exercise significantly decreased myocardial uptake rates of glutamate and free fatty acids but increased myocardial uptake of glutamate, glucose, and lactate.
- A negative correlation between altered myocardial glutamate uptake and pulmonary artery wedge pressure suggests impaired glutamate uptake during exercise in IHD.
Impact:
- Myocardial uptake, reflecting energy metabolism, is a more sensitive index than uptake rate for assessing cardiac metabolic changes.
- Findings highlight altered substrate utilization patterns in IHD during physical stress.
- This research provides insights into the metabolic adaptations and limitations of the ischemic heart during exercise.