Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion in the review.
Specific interventions included in the review
Comparative studies of ACE inhibitors versus placebo, or high dose versus low dose and placebo, were eligible for inclusion. Studies of withdrawal from ACE inhibitors were excluded. The included studies were of captopril, benazepril, cilazapril, ramipril, fosinopril, dalapril, spirapil, enalapril, imidapril and trandolapril. The duration of treatment ranged from 4 to 12 weeks.
Participants included in the review
Studies of people with a clinically established diagnosis of congestive heart failure with left ventricular dysfunction were eligible for inclusion. Studies with exclusively non-symptomatic participants were excluded, as were studies where the number of participants in each group was not available or where it was less than 50. The age of the participants in the included studies ranged from 55 to 67 years, and the proportion of males ranged from 63 to 96%. The duration of heart failure ranged from 1 month to 4 years, and 90% of the participants were in New York Heart Association class II or III.
Outcomes assessed in the review
To be eligible for inclusion, the studies were required to have conducted an exercise tolerance test (bicycle ergometer, treadmill, 6-minute walk). The outcome used in the review was exercise duration. If this measure with associated standard deviations (SDs) was not available, the study was excluded. In the included studies, exercise duration was assessed using a treadmill test or bicycle ergometer.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.