WASHINGTON – A high-intensity cardiac rehabilitation program safely improved quality of life, diastolic function, depressive symptoms, and physical fitness in patients with systolic heart failure and reduced ejection fraction in a randomized controlled trial.
In the subgroup of study participants over age 65, however, the benefits were limited and the dropout rate high, Dr. Christina Chrysohoou said at the annual meeting of the American College of Cardiology. "I think patients over age 65 may benefit more from a less-intensive exercise time and rest periods."
Bruce Jancin/Frontline Medical News
Dr. Christina Chrysohoou
Her study included 100 consecutive patients with a left ventricular ejection fraction (LVEF) below 30%; heart failure of ischemic etiology was present in 70%. One-third of subjects had an implantable cardioverter-defibrillator at study entry. All participants underwent pre-enrollment Holter monitoring with electrophysiologic follow-up as warranted. Participants were randomized to a high-intensity exercise program or to a control arm of standard dietary advice and a recommendation to walk for up to 2 miles daily, said Dr. Chrysohoou, a cardiologist at the University of Athens.
The exercise program consisted of a warm-up followed a 30-minute session of alternating 30-second bursts of ergometric exercise at 100% of a patient’s maximum workload followed by 30 seconds of recovery at 40%-60% of maximum workload. Maximum workload was determined from a baseline treadmill exercise test. The 12-week study was completed by 33 of 50 patients in the high-intensity exercise group and 39 of 50 controls.
Quality of life scores on the Minnesota Living with Heart Failure Questionnaire improved from a mean score of 21 at baseline to 7 in the intensive-exercise group, and declined slightly from 19 to 21 in the control group.
At baseline, the mean score on the Zung Depression Scale was 37 out of a possible 80; at 12 weeks, scores improved to 30 in the high-intensity exercise group and increased to 41 in the controls.
Maximal oxygen consumption, or VO2max, improved from 16 to 21 mL/kg per minute in the interval-exercise group while remaining unchanged in controls. Similarly, peak power output increased from 84 to 105 W in the exercise program participants while remaining unchanged in controls. Six-minute walk time improved from 422 m to 476 m in the intensive exercisers, a 13% better result than that seen in controls.
Diastolic function on Doppler imaging significantly improved in the exercise group but not in the controls. The E/A wave ratio, which represents the relationship between early passive left ventricular filling and atrial contraction in late diastole, decreased by 24%. Also, the left ventricular outflow velocity integral increased by 4%.
There were no adverse events in either study arm.
LVEF did not significantly improve in either study arm, but that was not surprising, said Dr. Chrysohoou. "You may have an LVEF of 20% and be able to run a marathon, or an LVEF of 30%-35% and not even be able to walk around the house."
This was an unfunded study, and Dr. Chrysohoou reported having no financial conflicts.