For instance, Loyola heart failure patient Rosemary Jakubowski of Elmwood Park said before she received cardiac resychronisation, she had experienced significant fatigue. 'I always had that dragging feeling,' she said.

Since receiving resychronisation, Jakubowski has been taking kickboxing and swim aerobics classes, without fatigue. 'I'm 100 percent better -- complete satisfaction,' she said. 'It's like I'm a new person.'

The Food and Drug Administration has approved cardiac resychronisation for patients with Class 3 (moderate) and Class 4 (severe) heart failure. Such patients experience marked limitations in physical activity or are unable to do any physical activity at all without discomfort.

'With this study, we have shown that certain patients with early-stage, mild heart failure also can benefit from cardiac resychronisation,' Wilber said.

These findings were published in the New England Journal of Medicine.