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[Do cardioselective beta-antagonists block the cardiac beta-receptor function also in the long run?]
S Yndgaard1, F K Lippert, P G Berthelsen
1Anaestesiologisk afdeling, Amtssygehuset i Gentofte.
Ugeskrift for Laeger
|May 26, 1998
Summary
Patients on beta-blockers show normal cardiovascular function due to compensatory mechanisms. Chronic use of beta 1-blockers in men undergoing surgery did not impair their cardiovascular beta-adrenoceptor sensitivity.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Human cardiomyocytes express both beta 1 and beta 2 adrenoceptors.
- Inhibition of one receptor type may be compensated by the other.
Purpose of the Study:
- To test the hypothesis that compensatory mechanisms can maintain cardiovascular function despite chronic beta 1-blocker treatment.
- To compare cardiovascular beta-adrenoceptor sensitivity in patients with and without prior beta-blocker exposure.
Main Methods:
- Study included 40 middle-aged men undergoing coronary artery bypass surgery.
- Patients were divided into two groups: chronic cardioselective beta 1-antagonist users (n=20) and never beta-blocked controls (n=20).
- Hemodynamic status and cardiovascular beta-adrenoceptor sensitivity to isoprenaline were assessed after standardized anesthesia.
Main Results:
- Hemodynamic status post-anesthesia was similar between the two groups.
- Cardiovascular beta-adrenoceptor sensitivity to isoprenaline titration was also similar in both groups.
- No significant difference in cardiovascular function was observed between chronic beta-blocker users and controls.
Conclusions:
- Patients chronically treated with cardioselective beta 1-blockers exhibit compensatory mechanisms.
- Cardiovascular function in these patients is indistinguishable from individuals never exposed to beta-blockers.
- The study supports the concept of receptor compensation in cardiovascular pharmacology.