Clinical study: radionuclide imaging
Exercise training improves biventricular oxidative metabolism and left ventricular efficiency in patients with dilated cardiomyopathy

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Abstract

Objectives

The aim of this study was to determine the effect of exercise training on myocardial oxidative metabolism and efficiency in patients with idiopathic dilated cardiomyopathy (DCM) and mild heart failure (HF).

Background

Exercise training is known to improve exercise tolerance and quality of life in patients with chronic HF. However, little is known about how exercise training may influence myocardial energetics.

Methods

Twenty clinically stable patients with DCM (New York Heart Association classes I through III) were prospectively separated into a training group (five-month training program; n = 9) and a non-trained control group (n = 11). Oxidative metabolism in both the right and left ventricles (RV and LV) was measured using [11C]acetate and positron emission tomography. Myocardial work power was measured using echocardiography. Myocardial efficiency for forward work was calculated as myocardial work power per mass/LV oxidative metabolism.

Results

Significant improvements were noted in exercise capacity (Vo2) and ejection fraction in the training group, whereas no changes were observed in the non-trained group. Exercise training reduced both RV and LV oxidative metabolism and elicited a significant increase in LV forward work efficiency, although no significant changes were observed in the non-trained group.

Conclusions

Exercise training improves exercise tolerance and LV function. This is accompanied by a decrease in biventricular oxidative metabolism and enhanced forward work efficiency. Therefore, exercise training elicits an energetically favorable improvement in myocardial function and exercise tolerance in patients with DCM.

Abbreviations

BP
blood pressure
DCM
dilated cardiomyopathy
HF
heart failure
HR
heart rate
kmono
[11C]acetate clearance rate
LV
left ventricle or ventricular
NYHA
New York Heart Association
PET
positron emission tomography
ROI
region of interest
RV
right ventricle or ventricular
Vo2
oxygen uptake

Cited by (0)

This study was supported in part by the Ministry of Education, the Aarne Koskelo Foundation, the Research Foundation of Orion Corporation, and the Finnish Cardiovascular Foundation.