Effects of exercise training on myocardial energy metabolism and ventricular function assessed by quantitative phosphorus-31 magnetic resonance spectroscopy and magnetic resonance imaging in dilated cardiomyopathy.
OBJECTIVE
The present study investigated changes in cardiac energy metabolism and function in patients with dilated cardiomyopathy (DCM) before and after exercise training (ET) with phosphorus-31 magnetic resonance spectroscopy (MRS) in combination with magnetic resonance imaging (MRI).


BACKGROUND
Exercise training might have a beneficial role on myocardial function and oxidative metabolism in DCM, but it is unclear whether the additional load on the failing heart leads to deterioration of cardiac energy metabolism.


METHODS
Twenty-four patients were randomized to an exercise (age 53 +/- 12 years) or a control (age 56 +/- 6 years) group. Supervised ET was performed for 2 months, followed by 6 months of self-regulated training. At baseline and 2 and 8 months, maximal exercise testing along with quantitative MRS and MRI studies were performed.


RESULTS
The effectiveness of ET was demonstrated by a 17% increase in peak oxygen uptake (p < 0.05). Exercise training improved left ventricular (LV) end-systolic volume (p < 0.05) and LV ejection fraction (30 +/- 15% vs. 37 +/- 15%; p < 0.01) but not right ventricular parameters. The improvement in cardiac function was not accompanied by changes in cardiac high-energy phosphate concentrations; phosphocreatine, adenosine triphosphate, and the phosphocreatine/adenosine triphosphate ratio were all unchanged after training.


CONCLUSIONS
The observation that LV function improved and LV energy metabolism remained unchanged suggests that the beneficial effect of ET on LV function is achieved without adversely affecting metabolism. These findings lend further support for the use of ET as an adjunct therapy in DCM.
Beer
Meinrad
M
Institut für Röntgendiagnostik, Universität Würzburg, Würzburg, Germany. beer@roentgen.uni-wuerzburg.de
Wagner
Doris
D
Myers
Jonathan
J
Sandstede
Jörn
J
Köstler
Herbert
H
Hahn
Dietbert
D
Neubauer
Stefan
S
Dubach
Paul
P
D002311:Cardiomyopathy, Dilated / Q000378:metabolism / Q000503:physiopathology*; D004734:Energy Metabolism; D005080:Exercise Test; D005081:Exercise Therapy; D017079:Exercise Tolerance; D005260:Female; D006352:Heart Ventricles / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010759:Phosphorus Isotopes; D013318:Stroke Volume; D016277:Ventricular Function, Left
D010759:Phosphorus Isotopes