A six-month exercise intervention in subclinical diabetic heart disease: effects on exercise capacity, autonomic and myocardial function

Sacre, Julian W., Jellis, Christine L., Jenkins, Carly, Haluska, Brian A., Baumert, Mathias, Coombes, Jeff S. and Marwick, Thomas H. (2014) A six-month exercise intervention in subclinical diabetic heart disease: effects on exercise capacity, autonomic and myocardial function. Metabolism, 63 9: 1104-1114. doi:10.1016/j.metabol.2014.05.007

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Author Sacre, Julian W.
Jellis, Christine L.
Jenkins, Carly
Haluska, Brian A.
Baumert, Mathias
Coombes, Jeff S.
Marwick, Thomas H.
Title A six-month exercise intervention in subclinical diabetic heart disease: effects on exercise capacity, autonomic and myocardial function
Journal name Metabolism   Check publisher's open access policy
ISSN 1532-8600
0026-0495
Publication date 2014-09
Year available 2014
Sub-type Article (original research)
DOI 10.1016/j.metabol.2014.05.007
Open Access Status
Volume 63
Issue 9
Start page 1104
End page 1114
Total pages 11
Place of publication Maryland Heights, MO, United States
Publisher W.B. Saunders
Collection year 2015
Language eng
Formatted abstract
Objective
Autonomic dysfunction may contribute to the etiology and exercise intolerance of subclinical diabetic heart disease. This study sought the efficacy of exercise training for improvement of peak oxygen uptake (VO2peak) and cardiac autonomic function in type 2 diabetic patients with non-ischemic subclinical left-ventricular (LV) dysfunction.

Materials/Methods
Forty-nine type 2 diabetic patients with early diastolic tissue Doppler velocity > 1 standard deviation below the age-based mean entered an exercise intervention (n = 24) or usual care (n = 25) for 6-months (controlled, pre-/post- design). Co-primary endpoints were treadmill VO2peak and 5-min heart-rate variability (by the coefficient of variation of normal RR intervals [CVNN]). Autonomic function was additionally assessed by resting heart-rate (for sympathovagal balance estimation), baroreflex sensitivity, cardiac reflexes, and exercise/recovery heart-rate profiles. Echocardiography was performed for LV function (systolic/diastolic tissue velocities, myocardial deformation) and myocardial fibrosis (calibrated integrated backscatter).

Results
VO2peak increased by 11% during the exercise intervention (p = 0.001 vs. − 1% in controls), but CVNN did not change (p = 0.23). Reduction of resting heart-rate in the intervention group (p < 0.05) was associated with an improvement in the secondary endpoint of heart-rate variability total spectral power (p < 0.05). However, baroreflex sensitivity, cardiac reflexes, and exercise/recovery heart-rate profiles showed no significant benefit. No effects on LV function were observed despite favorable reduction of calibrated integrated backscatter in the intervention group (p < 0.05).

Conclusions
The exercise intolerance of subclinical diabetic heart disease was amenable to improvement by exercise training. Despite a reduction in resting heart-rate and potential attenuation of myocardial fibrosis, no other cardiac autonomic or LV functional adaptations were detected.
Keyword Diabetic cardiomyopathies
Exercise tolerance
Heart rate
Left ventricular function
Type 2 Diabetes mellitus
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Human Movement and Nutrition Sciences Publications
School of Medicine Publications
 
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