Xamoterol in Severe Heart Failure - Xamoterol Heart Failure

Description:

Xamoterol for exercise tolerance in moderate to severe heart failure.

Hypothesis:

Xamoterol is a safe and effective treatment for moderate to severe heart failure despite treatment with diuretics and angiotensin converting enzyme inhibitors.

Study Design

Study Design:

Patients Screened: Not given
Patients Enrolled: 516
NYHA Class: III=(75%), IV=(25%)
Mean Follow Up: 3 months
Mean Patient Age: 62
Female: 27
Mean Ejection Fraction: 25% (measured in only 31% of patients)

Patient Populations:

CHF NYHA III/IV
Diuretics and ACE inhibitors
Clinical diagnosis and confirmation by one of the following:
increase CT ratio
fractional shortening < 20%
left ventricular ejection diameter diastolic >60mm
ejection fraction < 35%

Exclusions:

Women of childbearing age
recent (8 weeks) myocardial infarction
exercise limitation due to noncardiac disease
valvular disease
hypertrophic cardiomyopathy
chest pain limiting exercise
concurrent beta receptor agonist or antagonist

Primary Endpoints:

Exercise duration

Secondary Endpoints:

Symptoms of heart failure
Arrhythmia
Adverse events

Drug/Procedures Used:

Xamoterol (200 mg BID)

Concomitant Medications:

Furosemide (43%)
Potassium sparing diuretics (16%)
Thiazide (15%)
ACE inhibitors (33%)

Principal Findings:

In patients with severe CHF, Xamoterol in addition to diuretics and ACE inhibitors had no significant effect on clinical signs of heart failure.

There was a significantly greater mortality in patients randomized to Xamoterol. Within 100 days of randomization, 32 patients (9.1%) died in the Xamoterol group compared to 6 (3.7%) in placebo group.

Xamoterol reduced maximum exercise heart rate and systolic pressure but had no effect on VPDs post exercise, showed no arrhythmogenic activity, and had variable effects on 24 hour heart rate.

Interpretation:

Although not designed as a mortality study, the absence of clinical benefit and increased mortality would support that Xamoterol should be avoided in patients with heart failure. Experience with other beta-adrenergic antagonists has been more encouraging

References:

1. Lancet 1990;336;1-6. Final results

Keywords: Exercise Tolerance, Xamoterol, Diuretics, Heart Failure, Blood Pressure, Diastole, Heart Rate


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