Haemodynamic long‐term effects of metoprolol at rest and during exercise in essential hypertension.

Abstract

1 Twelve men with untreated essential hypertension in WHO stage I were studied on an outpatient basis to evaluate the haemodynamic long‐term effect of a new beta‐adrenoceptor blocker, metoprolol. 2 Oxygen consumption, heart rate, cardiac output (Cardiogreen) and intraarterial brachial pressure were recorded at rest in a supine and sitting position and during steady state work at 300, 600 and 900 kpm/min. 3 The subjects were treated with metoprolol (dose 50‐250 mg/day) as the sole drug for 1 year and the haemodynamic study was repeated. 4 Mean arterial blood pressure was reduced about 12% at rest and 9% during exercise. The heart rate was decreased about 22% at rest and 20% during exercise. There was no significant compensatory increase in the stroke volume and consequently the cardiac index was reduced about 22% at rest sitting and about 17% during exercise. There was no decrease in total peripheral resistance. 5 No side‐effects were seen. 6 The major haemodynamic long‐term effects of metoprolol in mild and moderate essential hypertension resemble those seen by other beta‐adrenoceptor blockers like alprenolol, atenolol and timolol. The study has not given support to the assumption that metoprolol should cause less depression in cardiac output than other beta‐adrenoceptor blockers. 1977 The British Pharmacological Society