Exercise training in dilated cardiomyopathy improves rest and stress cardiac function without changes in cardiac high energy phosphate metabolism
- Cameron J Holloway1,2,
- Sairia Dass2,
- Joseph J Suttie2,
- Oliver J Rider2,
- Pete Cox1,2,
- Lowri E Cochlin1,2,
- Hamish Jackson1,
- Angela M Fast1,
- Andrew W Johnson1,
- Theodoros D Karamitsos2,
- Stefan Neubauer2,
- Kieran Clarke1
- 1Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, UK
- 2University of Oxford Centre for Clinical Magnetic Resonance Research, (OCMR), Department of Cardiovascular Medicine, John Radcliffe Hospital, Oxford, UK
- Correspondence to Dr Cameron John Holloway, Department of Physiology, Anatomy and Genetics, The University of Oxford, Parks Road, Sherrington Building, Oxford OX1 3PT, UK; cameron.holloway{at}dpag.ox.ac.uk
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Contributors All authors contributed significantly to this study and manuscript. CH: Protocol development, performed all scans, blood analysis, data analysis and manuscript writing. SD: Assisted with scanning, data analysis and writing. JS: Assisted with scanning, bloods and analysis. OR: Data analysis and statistics. PC: Assisted with patient preparation and scanning. LC: Development of MR protocol and analysis. HJ: Analysis of MRS data. AF: Protocol development. AJ: Scanning and analysis of MR data. TK: Protocol development and editing manuscript. SN: Protocol development, study design and manuscript editing. KC: Conceived idea for project, funding and manuscript preparation. KC and SN are joint senior authors of this work.
- Accepted 1 May 2012
Abstract
Objective To determine the effects of short-term exercise training on cardiac function and metabolism during rest and physical exercise in patients with heart failure from dilated cardiomyopathy (DCM).
Design Patients with DCM (n=15, age 58±2 years, NYHA class I–III) were studied before and after 8 weeks of cycle exercise for 20 min, five times per week.
Main outcome measures Cardiac volumes, function and high energy phosphate metabolism were measured using cardiac magnetic resonance during rest and 7 min of acute physical exercise (leg-raising).
Results At baseline, average left ventricular ejection fraction (LVEF) was 38±3%, which did not alter during 7 min of exercise. After 8 weeks of home exercise training, there was a 16% improvement in resting LVEF to 44±3% (p<0.01). Training caused a further 20% improvement in LVEF (p<0.05) during acute physical exercise. There was a negative correlation between subjects' baseline level of exercise and change in LVEF (r=−0.67, p<0.05), with sedentary patients having the greatest improvement. Cardiac phosphocreatine (PCr) to ATP ratio did not change during acute physical exercise or after exercise training.
Conclusions Short-term exercise training improves resting LVEF and LVEF with acute physical exercise with sedentary patients having the greatest improvement. There were no changes in cardiac PCr to ATP, before or after exercise training, suggesting that the improved cardiac function was not caused by improved energetics. Therefore, peripheral factors likely underlie the improved cardiac function in patients with heart failure after short-term exercise.
- Dilated cardiomyopathy
- cardiac function
- cardiac energy metabolism
- quality of life
- insulin sensitivity
Footnotes
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Funding The British Heart Foundation (FS07/030) supported this work.
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Competing interests None.
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Ethics approval Ethics approval was provided by Oxrec.
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Provenance and peer review Not commissioned; internally peer reviewed.
