Myocardial gene expression in dilated cardiomyopathy treated with beta-blocking agents.

Background Beta-blocker therapy may improve cardiac function in patients with idiopathic dilated cardiomyopathy. We tested the hypothesis that beta-blocker therapy produces favorable functional effects in dilated cardiomyopathy by altering the expression of myocardial genes that regulate contractility and pathologic hypertrophy. Methods We randomly assigned 53 patients with idiopathic dilated cardiomyopathy to treatment with a β-adrenergic–receptor blocking agent (metoprolol or carvedilol) or placebo. The amount of messenger RNA (mRNA) for contractility-regulating genes (those encoding β1- and β2-adrenergic receptors, calcium ATPase in the sarcoplasmic reticulum, and α- and β-myosin heavy-chain isoforms) and of genes associated with pathologic hypertrophy (β-myosin heavy chain and atrial natriuretic peptide) was measured with a quantitative reverse-transcription polymerase chain reaction in total RNA extracted from biopsy specimens of the right ventricular septal endomyocardium. Myocardial levels of β-adr...