The cardiorespiratory response and physiological determinants of the assisted 6‐minute handbike cycle test in adult males with muscular dystrophy

Abstract

Introduction: The assisted 6‐minute cycle test (A6MCT) distance was assessed in adults with muscular dystrophy (MD). Methods: Forty‐eight males, including those with Duchenne MD (DMD), limb‐girdle MD (LGMD), fascioscapulohumeral MD (FSHD), and Becker MD (BMD), as well as a group without MD (CTRL), completed handgrip strength (HGS), lung function [forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC)], body fat, and biceps thickness assessments. During the A6MCT, ventilation (Ve), oxygen uptake (Vo 2), carbon dioxide (Vco 2), and heart rate (HR) were recorded. Results: A6MCT and HGS were lower in MD than CTRL subjects. FEV1, FVC, and biceps thickness were lower in MD than CTRL; lower in DMD than BMD, LGMD, and FSHD; but were not different between BMD, LGMD, and FSHD. A6MCT correlated with HGS, FEV1, FVC, body fat, Vo 2, Vco 2, HR, and Ve (r = 0.455–0.708) in pooled BMD, LGMD, and FSHD participants. Discussion: A shorter A6MCT distance in adult males with MD was attributable to HGS and lung function. The A6MCT is appropriate for assessment of physical function in adults with MD. Muscle Nerve 58: 427–433, 2018

238th ENMC International Workshop: Updating management recommendations of cardiac dystrophinopathyHoofddorp, The Netherlands, 30 November - 2 December 2018

“…In cycling tests, however, heart rate in boys with DMD increased comparably to that of healthy peers, reaching only slightly lower peak rate by its end [10] . Modest exercise training is possible, even in older patients with DMD, and assisted exercise increases beneficial training demands both on muscle and cardiovascular systems [11,12] . On the basis of current evidence, it seems that physical training is beneficial both for skeletal muscle and cardiovascular systems in these patients [12,13] .…”

Focus on left ventricular systolic and diastolic function in the assisted 6‐minute hand bike cycle test in muscular dystrophy

“…We thank Dr Fayssoil for his interest in our manuscript. 1 Following a review of the participants' medical histories from the physiotherapy centre where this work was conducted, we are now able to add information on the use of cardiovascular specific medication from our adult participants with muscular dystrophy (MD) who undertook the assisted 6-minute cycle test (A6MCT). Four, all of who had Becker muscular dystrophy (BMD), were prescribed beta blockers.…”

“…I read with great interest the article by Morse et al 1 describing significant reduction of the assisted 6-minute cycle test (A6MCT) in patients with muscular dystrophy, particularly in the Duchenne muscular dystrophy (DMD) group compared with the limb-girdle muscular dystrophy (LGMD), Becker muscular dystrophy (BMD), and facioscapulohumeral muscular dystrophy groups. This finding in DMD is associated with significant reduction of pulmonary function (vital capacity) and significant reduction of grip strength.…”

“…2 Heart function can be affected in dystrophinopathies and in some subtypes of LGMD. 3 Because the study by Morse et al 1 included patients with LGMD, BMD, and DMD, it may be useful to provide the prevalence of cardiac dysfunction and to evaluate the cardiac dysfunction contribution during the A6MCT in patients. Furthermore, left ventricular diastolic dysfunction and the arterial pressure profile may affect exercise tolerance in patients.…”

Reply‐ Focus on left ventricular systolic and diastolic function in the assisted 6‐minute hand bike cycle test in muscular dystrophy

“…We thank Dr Fayssoil for his interest in our manuscript . Following a review of the participants’ medical histories from the physiotherapy centre where this work was conducted, we are now able to add information on the use of cardiovascular specific medication from our adult participants with muscular dystrophy (MD) who undertook the assisted 6‐minute cycle test (A6MCT).…”