[Effects of selective beta adrenergic block on myocardial contractility. Relative role of negative inotropic and chronotropic effects].
Left ventricular function was studied in 15 patients both before and after intravenous administration of Practolol (an agent blocking selectively the heart beta-adrenergic receptors (beta 1)), while the heart rate was constant by right atrial pacing. The negative inotropic effect linked to the negative chronotropic effect of the beta-adrenergic blockage, represented approximately one quarter of the overall depression of the contractility. Right atrial pacing determined a decrease of the left ventricular end-diastolic pressure and an increase of the pacing rate by 20% above the spontaneous heart rate, after administration of 30 mg of Practolol, brought the contractility back to its control level.
D001145:Arrhythmias, Cardiac / Q000188:drug therapy*; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D002306:Cardiac Volume / Q000187:drug effects; D009202:Cardiomyopathies / Q000188:drug therapy; D004558:Electric Stimulation; D006327:Heart Block / Q000188:drug therapy; D006339:Heart Rate / Q000187:drug effects*; D007275:Injections, Intravenous; D009200:Myocardial Contraction / Q000187:drug effects*; D009203:Myocardial Infarction / Q000188:drug therapy; D011217:Practolol / Q000008:administration & dosage / Q000627:therapeutic use*
D011217:Practolol
Effets du blocage bêta-adrénergique sélectif sur la contractilité myocardique Rôle relatif des effets inotrope at chronotrope négatifs