Inclusion criteria for β blocker heart failure trials6-150
| USCP | CIBIS II | MERIT-HF | |
| Age (years) | 18–85 | 18–80 | 40–80 |
| NYHA class | II–IV | III–IV | II–IV |
| Duration of CHF (months) | 3 | 3 | 3 |
| Stability (weeks) | 4 | 2 | 2 |
| Diuretic | Required | Required | Required |
| ACE inhibitor | Required | Required | Required |
| Digoxin | Optional | Optional | Optional |
| Calcium antagonists | None | None6-151 | Rate limiting excluded |
| Antiarrhythmic drugs | Classes Ic and III excluded6-152 | Only amiodarone permitted | Amiodarone excluded |
| LVEF | ⩽0.35 | ⩽0.35 | ⩽0.40 |
| 6 minute walk | All (various criteria) | Not done | < 450 m if LVEF 0.36–0.40 |
| Heart rate (beats/min) | 68 | 60 | 68 |
| Systolic blood pressure (mm Hg) | 85 | 100 | 100 |
| Tolerability of β blocker (open label run in) | Required | Not required | Not required |
| Target dose (mg) | 25/50 mg bid6-153 | 10 mg od | 200 mg od6-154 |