Pathophysiology

Pathophysiology Study Guide

more common than rheumatic aortic stenosis, which is caused by a congenital malformation in which one less leaflet of the aortic valve is present. The normal size of the aortic orifice is between 3-5 cm 2 , which when reduced to half, causes a heart murmur and is termed as mild aortic stenosis. When the size is reduced to 0.7 to 1.0cm 2 , the phase is termed as moderate aortic stenosis, and when it reaches about 0.4cm 2 , severe aortic stenosis occurs. Symptoms include interference with blood pressure regulation, loss of consciousness, and angina (chest pain). Treatment of aortic stenosis is cardiac surgery. Causes of aortic regurgitation include rheumatic fever, infective endocarditis, a disease of the aortic root, and congenital deformity. Instances of rheumatic fever, and thus rheumatic aortic regurgitation, have decreased and most of the instances of aortic regurgitation are due to disease of aortic root. Diagnoses of aortic regurgitation include heart murmur, abnormal arterial pulse, unusually low diastolic blood pressure, and echocardiography using the Dipper principle. The consequences of this disorder vary from mild to severe and have the ability to cause heart failure. Tricuspid/Pulmonic Disease Other diseases of the valve include pulmonary and tricuspid stenosis and regurgitation. Pulmonary stenosis is congenital in nature. Pulmonary regurgitation is one of the rarest valvular diseases and is often caused due to severe pulmonary hypertension. In this case, the pulmonary valve does not function normally due to high pressure in the pulmonary artery. One of the rarest complications of rheumatic fever is Tricuspid stenosis and coexists along with mitral stenosis. Further, tricuspid regurgitation is mostly associated with pulmonary hypertension and leads to failure in the right ventricle of the heart. In this case, the valve does not function normally causing excessive stretching of the tricuspid orifice. The repair or replacement of the tricuspid valve is rare, as it is less effective when compared to that of the left-sided cardiac valves. Basic Mechanism Congestive heart failure occurs when the heart muscle pump function is impaired and is not able to meet the needs of the body. In this situation, the pump does not work efficiently due to the accumulation of fluid around the heart. The ventricles of the heart do not pump a sufficient amount of blood from the heart to the body tissues and organs, hence blood and fluid start to accumulate in the lungs, abdomen, liver, and lower body. When fluid gets congested in the body parts due to a weakening of pumping power of the heart, it is termed congested heart failure. Etiology Damage to the heart muscles is the leading cause of heart failure. Coronary artery disease causes 3.3 Cardiac Mechanisms/Heart Failure Congestive Heart Failure

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