Blokerer kardioselektive β-antagonister hjertets β-receptorfunktion ogsa pa laengere sigt?

As the human cardiomyocyte expresses both β₁ and β₂ adrenoceptors it is to be expected that the inhibition of one species of receptors can be counteracted by the other. This hypothesis was tested in 40 middle-aged men scheduled for coronary artery bypass surgery. Half the patients had been treated with cardioselective β₁ antagonists for more than three months while the 20 control patients had never been β-blocked. The haemodynamic status after induction of a standardized fentanyl/midazolam anaesthesia and the sensitivity of the cardiovascular β-adrenoceptors to isoprenaline titration were similar in both groups. In conclusion, patients chronically treated with cardioselective β₁-blockers compensate for the perturbation to such a degree that their cardiovascular function is indistinguishable from patients who have never received β-blockers.