European heart journal
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European heart journal · Oct 1993
Review Comparative StudyEffects of beta-blockers and calcium channel blockers in acute myocardial infarction.
beta-blockers and calcium channel blockers have been evaluated extensively during the acute phase and following myocardial infarction. beta-blockers, when administered early and intravenously, reduce early mortality, reinfarction and cardiac arrests by about 16%. The reduction in mortality is likely to be due to multiple mechanisms including reductions in cardiac rupture, reinfarction and ventricular fibrillation. Recent data also suggest a reduction in intracranial haemorrhage when administered in conjunction with thrombolytic therapy. ⋯ On the other hand, agents that reduce heart rate (verapamil and diltiazem) appear to have a neutral effect on mortality but may reduce reinfarction rates. The benefits of beta-blockers appear to be consistent in most subgroups of patients examined, whereas the adverse effects of calcium channel blockers are most marked in those with large infarcts or heart failure. In conclusion, beta-blockers are preferable to calcium channel blockers in the acute phase and long-term after myocardial infarction.
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European heart journal · Oct 1993
The link between acute haemodynamic adrenergic beta-blockade and long-term effects in patients with heart failure. A study on diastolic function, heart rate and myocardial metabolism following intravenous metoprolol.
The present study was performed to find possible mechanisms linking the early effects of beta-blockade with the observed long-term effects in patients with heart failure. In 57 patients with heart failure, 13 +/- 3.1 mg of metoprolol was given intravenously. The patients were investigated by invasive haemodynamics (n = 34), including collection of myocardial metabolic data during atrial pacing stress (n = 16), by radionuclide angiography during physiological atrial pacing (n = 13), and by a bedside evaluation (n = 10). ⋯ There was a trend towards an increase in myocardial lactate consumption after beta-blockade administration during atrial pacing stress. It is suggested that the surprisingly good tolerability seen after acute administration of beta-blockers to patients with severe heart failure may be explained by prolongation of the diastolic filling phase, which outweighs the negative inotropic effects. The reduced myocardial metabolic demand may allow the failing myocardium to recover and explain the excellent long-term effect on heart function following beta-blockade treatment.