Beta-adrenoceptor blockade and intrinsic sympathomimetic activity--relevance in the treatment of ischaemic heart disease.

Beta adrenoceptor blockade has become one of the major therapeutic interventions in the medical management of ischaemic heart disease over the last 15 years. A number of beta adrenoceptor blockers have been developed with differing pharmacological properties including cardioselectivity and intrinsic sympathomimetic activity (ISA). The relevance of this latter property has been in some doubt. A number of reports suggest that ISA confers haemodynamic benefits although there does not appear to be any clear therapeutic advantage. In addition it would appear that patients with severe or rest angina might benefit more from a pure beta antagonist rather than one with ISA when the beta blocker is used as monotherapy, but this situation rarely arises. This paper reviews and assesses the value of treatment of ischaemic heart disease with beta blockers possessing intrinsic sympathomimetic activity.