IPLab:Lab 2:Hypertrophy

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Contents

Clinical Summary

This 68-year-old man initially sought medical advice five years prior to his death. His symptoms at that time were exercise intoleranceExercise intolerance is the development of shortness of breath upon exertion. and occasional peripheral edemaPeripheral edema refers to the accumulation of fluid in the intercellular tissue spaces of the legs and ankles.. He gave a history of a "heart murmur" that was diagnosed 25 years ago during an employment physical. No follow up care had been given for this murmur.

The patient's terminal admission was for signs of severe heart failure -- the patient had marked peripheral edemaMarked peripheral edema is usually a manifestation of heart failure -- especially of the right ventricle. and shortness of breathShortness of breath is a common clinical manifestation of heart failure. and chest x-ray revealed significant cardiac enlargement and pulmonary edemaPulmonary edema refers to the accumulation of abnormal amounts of fluid in the extravascular spaces of the lungs. There are many causes for pulmonary edema. However, it is common clinical manifestation of left ventricular heart failure. Pressures rise in the left atrium and ventricle to compensate for the failure and this causes increased pressure in the pulmonary vasculature. Incrased pulmonary capillary pressure relative to the plasma oncotic pressure cause fluid to leave the vessels and enter the interstitial spaces of the lung. with bilateral pleural effusionsPleural effusion is the presence of fluid in the pleural space. Increased hydrostatic pressure in the pulmonary vasculature, as seen in heart failure, is one cause of pleural effusion.. He sustained a cardiac arrestCardiac arrest is the sudden standstill of cardiac function. shortly after admission and could not be resuscitated.

Autopsy Findings

Autopsy disclosed a markedly enlarged heart weighing 650 gramsA normal heart weighs 300 grams (range: 270 to 360 grams). and having dilated chambers. The aortic valve was calcified and showed evidence of stenosisAortic stenosis (calcification of the aortic valve) is the most common valve abnormality. Calcification of the valve leads to a reduced valve area. Increased pressure is thus needed from the left ventricle to pump blood into the aorta. Over time, the pressure-overloaded ventricle hypertrophies concentrically (increased ratio of wall thickness to cavity radius) in an attempt to reduce wall tension (review the Law of Laplace). Eventually, the left ventricle's contractile capacity is overwhelmed by the stiffness of the ventricle (due to hypertrophy) and pressure begins to increase through the left atrium and into the pulmonary vasculature. Increased pulmonary artery pressures then lead to right ventricular failure. and insufficiencyAortic insufficiency refers to the inability of the aortic valve to close properly, thus allowing regurgitation of blood into the left ventricle during diastole -- i.e., volume overload. Disease of the aortic valve leaflets is a common cause of insufficiency.. The coronary arteries were narrowed 60 to 70% by atherosclerosis. No acute coronary occlusions were found and there was no evidence of myocardial infarctionMyocardial infarction is necrosis of myocardial tissue which occurs as a result of a deprivation of blood supply, and thus oxygen, to the heart tissue. Blockage of blood supply to the myocardium is caused by occlusion of a coronary artery..

Images

Virtual Microscopy

Myocardial Hypertrophy

Normal Heart

Study Questions


Additional Resources

Reference

Journal Articles

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