ABSTRACT
Both the output of blood from the heart and the integrity of the blood vessels feeding the heart are needed to maintain an adequate delivery of oxygen and nutrients to the heart muscle. Saturated fatty acids in diets with too many calories have been implicated frequently in the progressive chronic onset of atherosclerosis with its resultant impaired blood flow described in Chapter 5. In contrast, polyunsaturated fatty acids of the n-6 type are associated more with the rapid aspects of hemostasis, thrombosis, and vascular spasm that involve thromboxane. Thromboxane A2 derived from arachidonic acid (20:4n-6) may induce arterial spasm, and it has been implicated in Prinzmetal’s angina. The fact that unstable angina and myocardial infarction can occur when a patient is at rest suggests that the primary cause of the problem was not a greater need for oxygen by an overexerting heart muscle, but a decreased delivery of oxygen to the heart muscle. The decreased oxygen supply could result from thrombus formation as described in Chapter 6 or from coronary vasoconstriction caused by either catecholamines or thromboxane.
