高血压英文ppt精品课件coronary

CORONARY ARTERY CORONARY ARTERY DISEASES Causes of coronary artery disease: Coronary stenosis or complete occlusion due to atheroma. Thrombosis, usually associated with atheroma. Coronary artery spasm. Dissecting coronary aneurysm. Myocardial bridging. ATHEROMA A fatty deposit in the intima (inner lining) of an artery, resulting from atherosclerosis. The most common cause of death from cardiovascular diseases is coronary atherosclerosis. Approximately half of the individuals with coronary artery disease die suddenly. Atheroma causes stenosis or occlusion to one or more of the major branches of the coronary arteries. It may be focal or diffused . And results in reduced blood flow, either by atheromatous lesion itself or by its complications (ulceration, rupture, haemorrhage or thrombosis). A cross-section of coronary artery that has significant luminal obstruction by an atheroma. A lipid-rich core can be seen in the center of the lesion. Sites of coronary artery occlusion: First 2 cm of the left anterior descending coronary artery. Right coronary artery. Circumflex coronary artery. Effects of coronary artery disease: Fatal cardiac arrhythmia. Myocardial infarction. Myocardial fibrosis. Postmortem findings: coronary atheroma. areas of myocardial fibrosis. rarely, areas of recent infarcts. CORONARY ARTERY SPASM At autopsy, there is no infarct and the coronary arteries are found to be patent, without significant atherosclerosis or congenital anomalies. Death is believed to be due to transitory coronary artery spasm. (coronary arteries spasm without anatomical narrowing of the coronary arteries, in association with angina) CORONARY ARTERY ANEURYSM It an intramural hematoma of the media of the vessel wall, which flattens and occludes the lumen, reducing the blood flow. A dissecting aneurysm of the coronary artery maybe, either secondary to extension of an aortic root dissection. Or primary and limited to the coronary artery. Primary dissecting aneurysms maybe either spontaneous, or due to trauma(eg. Chest trauma, coronary angiography). Spontaneous coronary artery dissections is a rare condition, mostly occurring in females particularly in the peripartum period. Usually presenting as sudden death. Cross photograph of ruptured aneurysm of right coronary artery and surrounding hemorrhage. CORONARY ARTERY ANEURYSM MYOCARDIAL BRIDGING occurs when the one of the coronary arteries (left anterior descending coronary artery rarely the right) tunnels through the myocardium rather than resting on top of it. Typically, the arteries rest on top of the heart muscle and feed blood down into smaller vessels that populate throughout the myocardium. But if the muscle grows around one of the larger arteries, then a myocardial bridge is formed. As the heart squeezes to pump blood, the muscle exerts pressure across the bridge and constricts the artery. MYOCARDIAL BRIDGING This defect is present from birth. This condition can cause complications such as vasospasm, angina pectoris, arrhythmia, uncomfortable. Which results in sudden death due to this abnormality. HYPERTENSIVE HEART DISEASE Sudden death in individual with hypertension is usually associated with and in most instances due to, accompanying atherosclerosis. H.T may kill in a number of ways, such as by renal failure, ruptured aneurysm or cerebral hemorrhage, but here we concerned with primary heart failure, a quite common cause of death. CARDIOMYOPATHIES The cardiomyopathies constitute a diverse group of diseases of both known and unknown etiology, characterized by myocardial dysfunction. The diseases are not the result of arteriosclerotic, hypertensive, congenital, or valvular disease. Can be grouped into 3 general categories : 1. Dilated. 2. Restrictive. 3. Hypertrophic. Cardiomyopathy may result in sudden death(during exercise) as a result of arrhythmia. VALVULAR HEART DISEASE Sudden death associated with valvular disease usually involves a floppy mitral valve or aortic stenosis. Rarely, sudden death will be due to an acute bacterial valvulitis. Postmortem findings - the valve is thickened, rigid, with fusion of the commissures in most cases. - the whole valve maybe unrecognizable, chalky mass, with a stenosed lumen. - left ventricular hypertrophy. - increase heart weight, up to (800-1000 gms). B. VASCULAR DISEASE Dissecting aortic aneurysm. Ruptured atheromatous aortic aneurysm. Cerebrovascular disease. DISSECTING AORTIC ANEURYSM A tear in the tunica intima results in blood splitting the tunica media. This produces a false lumen that can progress in an antegrade or retrograde direction. Rupture may occur back into the lumen or externally. Result of an intimal tear causing a false lumen between the media and the adventitia. Over 90% occur in the ascending aorta either just distal to the aortic valve or the left subclavian artery. It can rupture but more commonly dissection propagates distally, involving vessels branching off the aorta producing ischaemia in the kidneys, lower extremities, viscera or spinal cord (in descending order of probability). Can also undergo antegrade extension to produce acute aortic regurgitation, myocardial infarction and cardiac tamponade. RUPTURED ATHEROMATOUS AORTIC ANEURYSM When the aorta ruptures spontaneously, rather