Pharmacological treatment of ischaemic heart disease: Monotherapy vs combination therapy

Non-invasive treatment continues to be the mainstay of anti-ischaemic therapy. The imbalance between myocardial oxygen supply and demand provides the basis for myocardial ischaemia, which may present as symptomatic, asymptomatic or, in most cases, a mixture of the two. Both symptomatic and silent ischaemia are major prognostic indicators in patients with coronary artery disease and treatment should therefore be directed towards both the amelioration of symptoms and the resolution of the signs of ischaemia. Anti-ischaemic therapy may decrease oxygen demand, increase myocardial oxygen supply, or both. Interventional therapies, such as percutaneous transluminal coronary angioplasty and bypass grafting, improve supply but do not alter demand. Drug therapy is associated with a variety of effects upon both supply and demand, depending upon the agent used. Nitrates alter both myocardial oxygen supply and demand, while beta-blockers decrease myocardial oxygen demand. Calcium channel blockers reduce after load and myocardial contractility and, thus, lower oxygen demand, while the coronary artery relaxation that occurs in response to their use acts to increase supply. The use of combination therapy is considered by many to be the most rational approach to the treatment of myocardial ischaemia, in that it allows maximal reduction in demand and increase in supply.