Long-term effects of carvedilol in idiopathic dilated cardiomyopathy with persistent left ventricular dysfunction despite chronic metoprolol
Key result
Switching to carvedilol in metoprolol-unresponsive dilated cardiomyopathy improves LVEF ~7% but worsens peak VO2.
- P=0.045
- n=30
Why the study?
Although metoprolol benefits most heart failure patients, a subset survives long term without satisfactory clinical improvement, prompting evaluation of whether carvedilol provides benefits in DCM patients who are poor responders to chronic metoprolol.
Does switching to carvedilol improve left ventricular function and exercise tolerance in patients with dilated cardiomyopathy who are poor responders to chronic metoprolol?
Comparison
Cross over to carvedilol vs continuation of metoprolol
Design
Open-label, parallel randomized trial
Follow-up
12 months
Authors
Discussion
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Implication
In patients with dilated cardiomyopathy who remain symptomatic with left ventricular dysfunction on chronic metoprolol, switching to carvedilol improves systolic function and remodeling but may decrease peak oxygen consumption.
Key Points
- To determine whether switching to carvedilol provides clinical, functional, and antiarrhythmic benefits in dilated cardiomyopathy patients with persistent left ventricular dysfunction on chronic metoprolol.
- Enrolled 30 consecutive patients with idiopathic dilated cardiomyopathy, persistent left ventricular dysfunction (ejection fraction ≤40%), and low exercise capacity despite >1 year of metoprolol and ACE inhibitors.
- Conducted a 12-month open-label randomized trial assigning patients to continue metoprolol (n=16, mean 142±44 mg/day) or switch to carvedilol (n=14, mean 74±23 mg/day).
- Carvedilol significantly improved left ventricular ejection fraction (+7±3% vs. -1±2%, p=0.045) and decreased end-systolic volume (-7±5 vs. +6±4 ml/m², p=0.047) compared to metoprolol.
- Carvedilol reduced ventricular ectopic beats (-12±9 vs. +62±50 n/h, p=0.05) and couplets (-0.5±0.4 vs. +1.5±0.6 n/h, p=0.048).
- Peak oxygen consumption decreased in the carvedilol group compared with the metoprolol group (-0.6±0.6 vs. +1.3±0.5 ml/kg/min, p=0.03), with no significant difference in quality of life or symptoms.
Study Design
Type
RCT (n=30)
Blinding
Open-label
Randomization
Randomized
Structured PICO
Does switching to carvedilol improve left ventricular function and exercise tolerance in patients with dilated cardiomyopathy who are poor responders to chronic metoprolol?
P
Population
30 patients with dilated cardiomyopathy, persistent LV dysfunction, and reduced exercise tolerance despite chronic metoprolol therapy, followed for 12 months.
I
Intervention
Cross over to maximum tolerated dosage of carvedilol (mean dosage 74+/-23 mg/day) for 12 months.
C
Comparator
Continued treatment with metoprolol (mean dosage 142+/-44 mg/day) for 12 months.
O
Outcome
Changes in left ventricular dimensions (end-diastolic and end-systolic volumes), left ventricular ejection fraction, ventricular ectopic beats, couplets, symptoms, quality of life, and peak oxygen consumption at 12 months.surrogate
Main Result
Absolute Event Rate: 7% vs -1%
p-value: p=0.045
In patients with dilated cardiomyopathy who remain symptomatic with left ventricular dysfunction on chronic metoprolol, switching to carvedilol improves systolic function and remodeling but may decrease peak oxygen consumption.
Cite This Study
Lenarda et al. (1999) conducted an RCT in Idiopathic dilated cardiomyopathy (n=30). Carvedilol vs. Metoprolol (mean dosage 142+/-44 mg/day) was evaluated on Change in left ventricular ejection fraction (p=0.045). Switching to carvedilol in dilated cardiomyopathy patients poorly responsive to metoprolol improved LV ejection fraction (+7% vs -1%, p=0.045) but negatively affected peak oxygen consumption.