Comparative hemodynamic studies in man of adrenergic β₁‐receptor agents without (H 93/26 = metoprolol) or with (H 87/07) intrinsic sympathicomimetic activity

The two new cardioselective β‐adrenergic blocking agents H 93/26 and H 87/07 without and with intrinsic sympathicomimetic activity, respectively, were given intravenously to two groups of young healthy men to study the acute influences on systemic hemodynamics at rest and during standardized physical exercise. The findings indicate that H 93/26 exerts marked negative chronotropic effects both at rest and during physical exercise with only moderate negative inotropic effects resulting in significant reductions in cardiac output with no or only minor changes in stroke volume. In the present doses, a negative chronotropic effect of H 87/07 was, on the contrary, discernible first under strenous physical exercise, the drug exerting no effect on the systemic hemodynamics at rest. It is concluded that the set‐up used for obtaining hemodynamic data at rest and during physical strain could be a suitable and sensitive instrument to differentiate between various types of β‐adrenergic blocking agents.