Aerobic Training Reverses Left-Ventricular Remodeling in Stable Heart Failure

EDMONTON, Alberta, June 13 -- For patients with stable heart failure, cardiac rehabilitation that focuses on aerobic training can reverse left-ventricular remodeling and improve ejection fraction.

That finding emerged from a meta-analysis of 14 randomized controlled trials of exercise training in patients with heart failure published in the June 19 issue of the Journal of the American College of Cardiology.

Aerobic training significantly improved ejection fraction by a weighted mean difference of 2.59% (95% CI 1.44%-3.74%) at the same time that it significantly reduced end systolic volume and end diastolic volume, wrote Mark J. Haykowsky, Ph.D., of the University of Alberta here, and colleagues.

There was, however, no confirmed benefit for combining aerobic and strength training.

The 14 trials included clinically stable patients with heart failure symptoms and a weighted mean ejection fraction of 23% at baseline. The mean age of patients was 57, and 89% of the patients were men.

Nine of the trials studied aerobic exercise training, usually at 60% to 80% of baseline VO_{2 peak,} and four investigated combined aerobic and strength training regimens. One study investigated strength training alone.

The authors noted that when the findings of all trials were pooled, exercise training was associated with "a significant improvement in [ejection fraction]" but the analysis demonstrated substantial heterogeneity.

However, when the results of the aerobic trials were analyzed separately those results demonstrated "relatively consistent benefits" in the heart's pumping capacity for the 538 patients who participated.

The finding that strength training was not beneficial was unexpected, but the authors speculated that it might be due to "the heightened systolic and diastolic pressure loading that occurs with strength training. Moreover, the strength-training-mediated increase in LV wall stress, coupled with impaired contractile and preload reserve, could explain why LV stroke volume and [ejection fraction] do not increase with this type of exercise."

And while aerobic training was found to be beneficial, the authors could only speculate as to why this was so suggesting that "it may be due to the reduction in vasoconstrictive neurohormones or a decline in hemodynamic loading."

But the take home message was unambiguous-aerobic training is "an inexpensive and effective nondrug, nondevice, nonsurgical intervention that reverses ventricular remodeling and improves VO_{2 peak} in clinically stable individuals with [heart failure] and LV systolic dysfunction."