151. Cardiopulmonary Exercise Testing and Metabolic Myopathies
- Author
-
D. Paul Nicholls, Christopher B. Cooper, and Marshall Riley
- Subjects
Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Glycogenolysis ,Oxidative phosphorylation ,030204 cardiovascular system & hematology ,Oxidative Phosphorylation ,03 medical and health sciences ,0302 clinical medicine ,Muscular Diseases ,Mitochondrial myopathy ,Internal medicine ,medicine ,Humans ,Glycolysis ,Lactic Acid ,Exercise physiology ,Exercise Tolerance ,Pulmonary Gas Exchange ,business.industry ,Skeletal muscle ,Lipid metabolism ,Carbon Dioxide ,medicine.disease ,Oxygen ,Citric acid cycle ,Endocrinology ,medicine.anatomical_structure ,Exercise Test ,business ,030217 neurology & neurosurgery - Abstract
Skeletal muscle requires a large increase in its ATP production to meet the energy needs of exercise. Normally, most of this increase in ATP is supplied by the aerobic process of oxidative phosphorylation. The main defects in muscle metabolism that interfere with production of ATP are (1) disorders of glycogenolysis and glycolysis, which prevent both carbohydrate entering the tricarboxylic acid cycle and the production of lactic acid; (2) mitochondrial myopathies where the defect is usually within the electron transport chain, reducing the rate of oxidative phosphorylation; and (3) disorders of lipid metabolism. Gas exchange measurements derived from exhaled gas analysis during cardiopulmonary exercise testing can identify defects in muscle metabolism because V.o2 and V.co2 are abnormal at the level of the muscle. Cardiopulmonary exercise testing may thus suggest a likely diagnosis and guide additional investigation. Defects in glycogenolysis and glycolysis are identified by a low peak V.o2 and absence of...
- Published
- 2017