HF may result from a number of causes that affect preload (venous return), afterload (impedance the heart has to overcome to eject its volume), or contractility. Elevated preload can be caused by incompetent valves, renal failure, volume overload, or a congenital left-to-right shunt. Elevated afterload occurs when the ventricles have to generate higher pressures in order to overcome impedance and eject their volume. This disorder may also be referred to as an abnormal pressure load. An elevation in afterload also may be caused by hypertension, valvular stenosis, or hyper-trophic cardiomyopathy. Abnormal muscle conditions may diminish contractility and cause a decrease in the ability of the heart muscle to act as a pump. Some common causes of diminished contractility include cardiomyopathy, coronary artery disease, acute myocardial infarction, myocarditis, amyloidosis, sarcoidosis, hypocalcemia, hypomagnesemia, or iatrogenic myocar-dial damage caused by drugs (adriamycin or disopyramide) or radiation therapy for mediastinal tumors or Hodgkin's disease.

Your Heart and Nutrition

Your Heart and Nutrition

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