A diagnostic cycle test for McArdle's disease.
We investigated whether the second wind phenomenon (ie, a decrease in heart rate and perceived exertion during exercise) is pathognomonic for McArdle's disease. Twenty-four patients with McArdle's disease, 17 healthy subjects, and 25 patients with other inborn errors of muscle metabolism cycled a constant workload for 15 minutes. In McArdle's disease patients, heart rate consistently decreased by 35 +/- 3 beats per minute from the 7(th) to the 15(th) minute of exercise, whereas heart rate increased progressively with exercise in all 42 control subjects. The findings indicate that cycling at a moderate, constant workload provides a specific, sensitive, and simple diagnostic test for McArdle's disease.
Vissing
John
J
Department of Neurology and Copenhagen Muscle Research Center, National University Hospital, Rigshospitalet, Copenhagen, Denmark. vissing@rh.dk
Haller
Ronald G
RG
D016022:Case-Control Studies; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D005081:Exercise Therapy; D005260:Female; D006012:Glycogen Storage Disease Type V / Q000175:diagnosis* / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008661:Metabolism, Inborn Errors / Q000175:diagnosis* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013997:Time Factors