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Aortic regurgitation (AR), also known as aortic insufficiency (AI), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. As a consequence, the cardiac muscle is forced to work harder than normal.
Often expressed in cm/s. This value is inversely related to the total cross-sectional area of the blood vessel and also differs per cross-section, because in normal condition the blood flow has laminar characteristics. For this reason, the blood flow velocity is the fastest in the middle of the vessel and slowest at the vessel wall.
Progressive overload not only stimulates muscle hypertrophy, but it also stimulates the development of stronger and denser bones, ligaments, tendons and cartilage. [5] Progressive overload also incrementally increases blood flow to regions of the body exercised and stimulates more responsive nerve connections between the brain and the muscles ...
The symptoms of TACO can include shortness of breath , low blood oxygen levels , leg swelling (peripheral edema), high blood pressure (hypertension), and a high heart rate (tachycardia). [ 3 ] It can occur due to a rapid transfusion of a large volume of blood but can also occur during a single red blood cell transfusion (about 15% of cases). [ 2 ]
It is measured as the amount of blood regurgitated into a cardiac chamber divided by the stroke volume. This fraction affords a quantitative measure of the severity of the valvular lesion. Normally, no blood regurgitates, so the regurgitant fraction is zero. In patients with severe valvular lesions, regurgitant fraction can approach 80%.
Afterload is the mean tension produced by a chamber of the heart in order to contract. It can also be considered as the ‘load’ that the heart must eject blood against. Afterload is, therefore, a consequence of aortic large vessel compliance, wave reflection, and small vessel resistance (LV afterload) or similar pulmonary artery parameters (RV afterload
Pressure overload may affect any of the four chambers of the heart, though the term is most commonly applied to one of the two ventricles. Chronic pressure overload leads to concentric hypertrophy of the cardiac muscle, which can in turn lead to heart failure , myocardial ischaemia or, in extreme cases, outflow obstruction.
The concept of allostatic load provides that "the neuroendocrine, cardiovascular, neuroenergetic, and emotional responses become persistently activated so that blood flow turbulences in the coronary and cerebral arteries, high blood pressure, atherogenesis, cognitive dysfunction, and depressed mood accelerate disease progression."