Increased plasma concentrations of angiotensin Ⅱ (Ang Ⅱ) have been implicated in many cardiovascular diseases such as atherosclerosis, aortic aneurysms and myocardial infarction in humans.However, it is not known whether high levels of plasma Ang Ⅱ affect coronary plaque rupture and subsequent myocardial infarction.To examine the above hypothesis, we infused Ang Ⅱ via osmotic minipumps into Watanabe heritable hyperlipidemic (WHHL) rabbits which are genetically deficient in low density lipoprotein receptors.WHHL rabbits have been used as a model for the study of human familial hypercholesterolemia and atherosclerosis.