Reduction in infarct size and enhanced recovery of systolic function after coronary thrombolysis with tissue-type plasminogen activator combined with beta-adrenergic blockade with metoprolol.
The effect of beta-adrenergic blockade on the salvage and functional recovery of reperfused myocardium was investigated in anesthetized dogs. Immediately after thrombotic occlusion of the left anterior descending coronary artery, the cardioselective beta-blocking agent metoprolol was given intravenously at a dose of 0.5 mg/kg infused over 10 min. One hour after the onset of occlusion, recanalization was initiated by intravenous infusion of recombinant human tissue-type plasminogen activator (rt-PA, 10 micrograms/kg/min for 30 min). Anatomic infarct size expressed as percent of the left ventricular mass (I/LV), global ejection fraction, and mean systolic shortening of the segmental radii (SS) of the infarcted area were measured either after 24 hr or 1 week in six groups of six dogs each: group I (rt-PA + metoprolol, evaluated at 24 hr), group II (rt-PA + metoprolol, evaluated at 1 week, group III (rt-PA alone, evaluated at 24 hr), group IV (rt-PA alone, evaluated at 1 week), group V (persistent occlusion, evaluated at 24 hr), and group VI (persistent occlusion, evaluated at 1 week). The smallest infarcts were found in reperfused dogs given metoprolol, but the differences from dogs receiving rt-PA alone were not statistically significant (I/LV, expressed as mean +/- SEM: 5.5 +/- 0.9% in group I, 6.7 +/- 1.9% in group II, 15.4 +/- 5.0% in group III, 11.4 +/- 3.5% in group IV, 23.6 +/- 2.5% in group V, and 26.9 +/- 2.3% in group VI).(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D003327:Coronary Disease / Q000188:drug therapy*; D003328:Coronary Thrombosis / Q000188:drug therapy* / Q000401:mortality / Q000503:physiopathology; D004285:Dogs; D004353:Drug Evaluation, Preclinical; D004359:Drug Therapy, Combination; D006439:Hemodynamics / Q000187:drug effects; D008790:Metoprolol / Q000627:therapeutic use*; D009200:Myocardial Contraction / Q000187:drug effects*; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000401:mortality / Q000503:physiopathology; D011994:Recombinant Proteins / Q000627:therapeutic use; D013599:Systole / Q000187:drug effects*; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*
D011994:Recombinant Proteins; D010959:Tissue Plasminogen Activator; D008790:Metoprolol