title: Effects of beta receptor antagonists on left ventricular function in patients with clinical evidence of heart failure after myocardial infarction. A double-blind comparison of metoprolol and xamoterol. Echocardiographic results from the Metoprolol and Xamoterol Infarction Study (MEXIS).
abstract: Two hundred and ten patients with clinical evidence of heart failure, developing after an acute myocardial infarction, were randomized to treatment with the beta 1-receptor antagonist metoprolol 50-100 mg b.i.d. (n = 106) or the beta 1-receptor partial agonist xamoterol 100-200 mg b.i.d. (n = 104). Left ventricular systolic and diastolic function were assessed with echocardiography and transmitral Doppler cardiography before and after 3 and 12 months of double-blind treatment. E-point septal separation and percent left ventricular fractional shortening were used as indices of systolic function. The ratio between peak early and late mitral diastolic flow (E/A ratio) and isovolumic relaxation time were used as indices of diastolic function. In the xamoterol group, there was a deterioration in E-point septal separation (P < 0.05). A difference between the treatment groups was present both at 3 months (E-point septal separation 11.4 vs 13.0 mm, P < 0.01, fractional shortening 27.1 vs 25.2%, P < 0.05) and 12 months (E-point septal separation 11.1 vs 13.2 mm. P < 0.005, fractional shortening 26.9 vs 25.0%, P < 0.05). E/A ratio increased in the metoprolol group (P < 0.05) but not in the xamoterol group. At 3 months there was a significant difference (0.85 vs 0.67, P < 0.005) between the groups but not at 12 months. In comparison with the beta 1-receptor antagonist metoprolol, the beta 1-receptor partial agonist xamoterol impaired left ventricular systolic function in patients with clinical evidence of heart failure after an acute myocardial infarction.
authors: Section of Cardiology, Karolinska Institutet, Danderyd Hospital, Sweden.
authors: H
authors: H
authors: Persson
authors: S V
authors: SV
authors: Eriksson
authors: L
authors: L
authors: Erhardt
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D002303:Cardiac Output, Low / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000209:etiology*; D004311:Double-Blind Method; D004452:Echocardiography; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications*; D016277:Ventricular Function, Left / Q000187:drug effects*; D017307:Xamoterol / Q000627:therapeutic use
chemical_list: D000319:Adrenergic beta-Antagonists; D017307:Xamoterol; D008790:Metoprolol