Metoprolol-induced functional benefit in dilated cardiomyopathy is sustained over four years and favorably influences outcome.
BACKGROUND
Beta-blockers improve survival and ventricular function in patients with heart failure. We evaluated the long-term persistence of metoprolol-induced improvement and its impact on prognosis in idiopathic dilated cardiomyopathy.


METHODS
Two hundred and four of 586 patients enrolled in a registry on the natural history of idiopathic dilated cardiomyopathy survived 4 years without transplantation; 98 of them were on standard heart failure treatment, whereas 106 took metoprolol in addition. We analyzed the effects of treatment using beta-blockers in terms of changes in left ventricular ejection fraction (LVEF), NYHA functional class and left ventricular end-diastolic diameter index (LVEDDI) after 1, 2 and 4 follow-up years in order to elaborate an improvement score that was related to the subsequent outcome over 60 months after the 4-year follow-up visit.


RESULTS
Greater LVEF increases and NYHA functional class and LVEDDI decreases were observed in patients submitted to metoprolol vs standard treatment at all stages of follow-up. Changes (delta vs baseline) for LVEF (p = 0.02), NYHA functional class (p = 0.0001) and LVEDDI (p = 0.004) were maximal during the first year (10 +/- 11 vs 6 +/- 12 units, -0.72 +/- 0.77 vs -0.23 +/- 0.81, -3.5 +/- 5 vs -1.6 +/- 3.5 mm), persisted at 2 (12 +/- 12 vs 8 +/- 12 units, -0.80 +/- 0.70 vs -0.37 +/- 0.87, -4.2 +/- 5 vs -2.3 +/- 4 mm) but showed a trend to decline at 4 years (11 +/- 12 vs 8 +/- 13 units, -0.54 +/- 0.90 vs -0.24 +/- 0.91, -4.3 +/- 5 vs -2.3 +/- 5 mm) of follow-up. Improvement at 4 years was associated with a better transplant-free survival (81 vs 52%, p = 0.0005, odds ratio 0.36, 95% confidence interval 0.18 to 0.74).


CONCLUSIONS
In idiopathic dilated cardiomyopathy, the more significant improvement in symptoms and left ventricular function and size, that is observed following treatment using metoprolol, translates into a better outcome. These benefits peak within the first 2 years of start of treatment but may begin to fade thereafter.
De Maria
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R
CNR Institute of Clinical Physiology, Milan, Italy. ifcnig@tin.it
Di Lenarda
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Gavazzi
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A
Porcu
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M
Sinagra
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Parolini
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M
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D002311:Cardiomyopathy, Dilated / Q000188:drug therapy* / Q000401:mortality / Q000503:physiopathology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008790:Metoprolol / Q000494:pharmacology / Q000627:therapeutic use*; D011379:Prognosis; D016019:Survival Analysis; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists; D008790:Metoprolol