The Effects of B-receptor Antagonists in Patients with Clinical Evidence of Heart failure After Myocardial Infarction: Double Blind Comparison of Meto - MEXIS


Xamoterol vs. metoprolol for exercise tolerance in heart failure.


Xamoterol will improve exercise tolerance more than metoprolol in post myocardial patients with heart failure because of its partial agonist activity.

Study Design

Study Design:

Patients Screened: Not given
Patients Enrolled: 210
NYHA Class: I=(3%), II=(68%), III=(29%)
Mean Follow Up: 12 months
Mean Patient Age: 66 (43-80)
Female: 18
Mean Ejection Fraction: Not obtained

Patient Populations:

Patients aged 40-80 years with one or more specified clinical or radiological signs of left ventricular failure at any time one week post myocardial infarction.


Severe congestive heart failure
Valvular disease
Hypertrophic cardiomyopathy
Pulmonary disease
Unstable angina
Inability to carry out exercise test
Diuretics, digoxin, ACE inhibitors, nitrates allowed
Calcium channel blockers

Primary Endpoints:

Exercise tolerance at 3 months

Secondary Endpoints:

Exercise tolerance at 6 and 12 months
Clinical assessment of heart failure
Quality of Life during treatment
Echocardiographic wall motion score

Drug/Procedures Used:

Metoprolol (50-100 mg BID)
Xamoterol (100-200 mg BID)

Concomitant Medications:

Furosemide (99%)
Digoxin (11%)
Beta blockers (19%)
Nitrates (87%)
ACE inhibitors (11%)
Calcium channel blockers (1%)
Potassium supplements (25%)
Thrombolytics (59%)

Principal Findings:

Exercise time increased by 22% in Metroprolol group and 29% in Xamoteral group (not statistically significant).

Quality of Life, clinical assessment improved in both groups with breathlessness being significantly better in xamoterol group at six months.

Mortality 4.7% for metroprolol; 5.8% for xamoterol.

17% withdrawals in metroprolol group; 22% xamoterol group.


Both metoprolol and xamoterol were associated with improved exercise time, quality of life and symptoms of heart failure with few patients showing deterioration. Whether or not this improvement is related to drug effect in either group cannot be determined due to absence of a control group.


1. Br Heart J 1995;74:140-8. Final results

Clinical Topics: Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: Exercise Tolerance, Myocardial Infarction, Quality of Life, Xamoterol, Heart Failure, Dyspnea, Metoprolol

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