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Carvedilol Insuficiencia Cardiaca (Heart Failure) Beta-Receptor - CARIBE
Description:
Carvedilol vs. placebo for ventricular and cardiac adrenergic function in heart failure.
Hypothesis:
Carvedilol improves ventricular and cardiac adrenergic function in patients with heart failure.
Study Design
Study Design:
Patients Screened: Not given
Patients Enrolled: 30
Patient Populations:
Stable class II or III heart failure
Left ventricular ejection fraction ≤35%
Primary Endpoints:
Ventricular and cardiac adrenergic function in patients with heart failure.
Drug/Procedures Used:
Placebo or carvedilol, increased weekly from 6.25mg b.i.d. to 25mg t.i.d. according to tolerance.
Principal Findings:
The CARIBE investigators evaluated the effect of carvedilol on left ventricular and cardiac adrenergic function in patients with stable chronic heart failure (CHF) due to idiopathic dilated cardiomyopathy. Thirty patients were randomized (10 to placebo) in this double-blind trial. Five patients withdrew from treatment in the carvedilol group (1 drug intolerance, 4 non-compliance) and 3 patients withdrew in the placebo group (1 drug intolerance, 1 change in the therapeutic schedule, and 1 death).
Carvedilol added to usual care in this heart failure population led to a decrease of about 20 beats per minute in heart rate (p=0.016), improved left ventricular (LV) function, and improved iodine123 metalodobenzylguanidine (MIBG) uptake on cardiac scintigraphy.
The beneficial effects of carvedilol on LV performance, which increased from 21% to 28%, was observed in early and late follow-up and was associated with an improvement in noradrenaline analogue uptake. However, there was no correlation between LV ejection fraction and MIBG uptake changes.
There was no significant difference in LV diastolic diameter on echocardiogram between the placebo and the carvedilol groups during follow-up.
Interpretation:
Low-dose beta-blockade appears to improve morbidity and mortality in selected populations of patients with dilated cardiomyopathy. Larger studies of carvedilol have used run-in periods to select patient populations likely to benefit from therapy; the high withdrawal rate (25%) in the treatment group suggests that compliance with therapy needs to be monitored closely. The small sample size of this study limits its statistical power to detect differences between the treatment and control groups. Imaging with MIBG, a norepinephrine analogue, may be useful for monitoring changes in cardiac adrenergic neuronal function, and eliciting the mechanism of benefit from beta-blockade.
References:
1. Circulation 1998;98(Suppl I):I-365. Preliminary results
Keywords: Myocardial Perfusion Imaging, Radioisotopes, Ventricular Function, Left, Norepinephrine, Propanolamines, Electrocardiography, Heart Rate, Carbazoles, Heart Failure, Stroke Volume, Cardiomyopathy, Dilated
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