Are patients chronically treated with β1-adrenoceptor antagonists in fact β-blocked?

Stig Yndgaard*, Freddy K. Lippert, Preben G. Berthelsen

*Corresponding author for this work
13 Citations (Scopus)

Abstract

Objective: To determine cardiovascular β-receptor function in patients with ischemic heart disease chronically treated with β1-adrenoceptor antagonists. Design: Prospective, single-blind, nonrandomized clinical trial. Setting: University Department of Cardiothoracic Anesthesia. Participants: Forty middle-age men scheduled for primary elective coronary artery bypass surgery. Twenty patients were treated with β1-antagonists. Interventions: After induction of anesthesia, increasing intravenous bolus doses of isoproterenol were administered in order to increase heart rate more than 25 BPM. From this dose-response curve, the isoproterenol dose needed to increase heart rate by exactly 25 BPM was calculated. Measurements and Main Results: Baseline cardiovascular variables and the pharmacodynamic responses to isoproterenol were monitored with catheters in the radial and the pulmonary artery (thermodilution catheter). Heart rate was continuously calculated from the electrocardiogram. The hemodynamic status after induction of a standardized fentanyl anesthesia and the chronotropic and inotropic responses to the isoproterenol titration procedure were identical in the 20 β1- blocked patients and in the 20 control patients. The median dose of isoproterenol needed to increase heart rate 25 BPM was 10.9 μg in the β- blocked patients and 9.4 μg in the control group. Conclusion: Patients chronically treated with β1-antagonists compensate for the perturbation to such a degree that cardiovascular β-receptor function is in fact normal.

Original languageEnglish
JournalJournal of Cardiothoracic and Vascular Anesthesia
Volume11
Issue number1
Pages (from-to)32-36
Number of pages5
ISSN1053-0770
DOIs
Publication statusPublished - 1 Jan 1997

Keywords

  • anesthesia
  • coronary artery bypass surgery
  • β-adrenoceptor sensitivity

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