Medicine of the Future in America

Myocardial Oxygen Supply and Demand: Coronary Artery Disease and Supply and Demand (3)

Myocardial Oxygen Supply and Demand: Coronary Artery Disease and Supply and Demand (3)Looking back at the factors impacting blood supply, one can see that an increase in diastolic phase may have a dramatic impact on subendocardial perfusion. On the demand side, the importance of controlling heart rate is again evident, as well as a reduction in wall tension through decreasing preload and afterload.
The management of patients with coronary artery disease is composed of behavioral modifications, correction of risk factors, medicopharmacologic therapy, and revascularization procedures. Pharmacologic therapy of patients with atherosclerotic coronary artery disease has undergone major directional changes over the past two decades. Traditionally, medical therapy had focused on increasing supply to the jeopardized myocardium (nitrates); however, newer groups of agents aim at reducing oxygen requirement of the heart. The medicopharmacologic armementarium is made up of three classes of agents (excluding antiplatelet agents): 1) nitrates, 2) beta adrenergic receptor blockers, and 3) calcium channel blockers. buy ampicillin
Nitrates relax vascular smooth muscles of venous and coronary arterial circulation. The vasodilatory effect of nitrates on coronary arteries yields increased supply of oxygen to the myocardium (Fig 3).


Figure 3. Effect of nitrates, beta adrenoreceptor blockers, and calcium channel blockers on myocardial oxygen supply and demand. Reflex effects are not shown.

This entry was posted in Pulmonary function and tagged artery disease, coronary artery, ischemia, myocardial oxygen.
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