CVS Practical 2 Please work in your PBL Tutorial group. Please submit your answers at the end of the practical.

CVS Practical Case 1 A 65 year old male with a history of angina and on regular medication suddenly collapsed whilst returning home from the market carrying a bag of rice. He was rushed to the hospital by ambulance but was certified dead at the Accident & Emergency Department. His death was reported to the Coroner. An autopsy was performed and the heart is shown in Figure 1.

Case 1 Figure 1.

Case 1 Questions about Fig. 1 What is the structure demonstrated (arrow)? This is a coronary artery. What is the exact anatomical name of this structure? This is the Anterior Descending branch of the Left Coronary artery What is the pathological lesion shown? The coronary artery lumen is occluded by an atheromatous plaque as well as a thrombus.

Microscopy of the lesion is shown here. Case 1 Figure 2

Case 1 Questions about Fig. 2 Describe what you see in Fig. 2 This is a low power view of a coronary artery. It is occluded by an atheromatous plaque which shows specks of calcification. The lumen is totally occluded by a superimposed red thrombus. Suggest a pathogenetic mechanism of this lesion. Several pathogenetic mechanisms could be taking place and they include:- disruption of flow, endothelial damage and possible disruption or ulceration of the atheromatous plaque with subsequent thrombotic occlusion of the lumen

Case 1 Figure 3

Case 1 Questions about Fig. 3 Figure 3 shows a microscopic section of the myocardium which appears normal. How can this be explained in light of all the other findings and the history available? The normal appearance of the myocardium is because the patient died very quickly and there was insufficient time for the pathological changes of infarction to show.

Case 1 Questions about Fig. 4 Fig. 4 shows a horizontal slice made through the heart. It was stained with a dye called nitro-blue tetrazolium. The normal myocardium will stain blue. Lesion A represents a silvery white area of fibrous scarring and infarct which represents old infarct with fibrous replacement. Lesion B represents areas of fresh myocardium infarction. Here the leaked enzymes from damaged cells act on the dye rendering it “colourless”.

CVS Practical Case 2 This is a 75 year old lady who had a myocardial infarction several years ago. Ever since then, her condition has gradually deteriorated. She sleeps only while lying semi-reclined. She notices swelling of both legs in the evening. She needs to urinate several times at night. She was found dead in bed at home. An autopsy was performed.

Case 2 Figure 1

Case 2 Questions on Fig. 1 Describe what you can see of the heart at autopsy. There is extensive fibrous scarring of the left ventricular wall. What are the reasons for her sleeping semi-reclined? She was orthopnoeic due to pulmonary congestion and oedema. Why is there swelling of the legs in the evening? This is due to the gradual build up of oedema as a result of poor venous return in a person with congestive heart failure. Why does she need to urinate several times at night? At night, patients lie down and lift up their legs, this improves the venous return and thus also the cardiac output. Improved cardiac output improves renal perfusion and therefore increases production of urine leading to frequent urination at night in such patients.

Case 2 Figure 2

Case 2 Questions on Fig. 2 This is a section of the ventricular wall seen under the microscope. Describe what you see that is different from Figure 2 of Case 1. It should be easily appreciated that there are areas of “loss” of myocytes and these areas are replaced by fibrous connective tissue.

Case 2 What is the mostly likely reason for the death of this patient? This patient most likely died when the right sided heart failure became so severe it also affected the left side of the heart. Alternatively, she could also have sustained a sudden fatal cardiac arrthymia.

CVS Practical Case 3 A 50 year old intravenous heroin addict was found dead inside a refuse room in a public housing estate. No used syringes were found next to his body. At the autopsy, the heart appears as in Fig. 1

Case 3 Fig. 1

Case 3 Questions on Fig. 1 Describe what you see. Where is the lesion located? What is the likely nature of the lesion? There is a large globular lesion (vegetation) situated over the mitral valve leaflet. This is likely to be an infective vegetation. What are the different type of damage that can happen to heart valves? Mechanical damage, degenerative damage and inflammatory/infective damage. How can one predict what the likely damage to a valve may have been by studying the appearance of a valve? The size, shape and appearance of a valve together with the appearance of its leaflets, commissures, etc can help us.

Case 2 Fig. 2

Case 3 Questions on Fig. 2 A microscopic section of the lesion at low power is shown. Compare this with Fig. 3 which is the appearance when taken from a normal heart. What is the likely pathogenesis of this lesion? This is an infective vegetation and as such is due to infection, inflamation and thrombosis. It is likely to have arisen from a bactereamia.

Low power view of a mitral valve leaflet. The distal deformity is a result of processing as well as representing the attachment for the chordae tendinae. Case 3 Fig. 3

Case 3 Finding 3 A higher power magnification of the lesion is shown in Fig. 4. Describe what you see. The lesion is made up of fibrin with abundnat lymphocytes and also clumps of bacteria (bluish smudges). What is the predominant cellular type seen? We see predominantly lymphocytes. Why would this person die? Patients die either from septiceamia or occasionally from cerebral abscesses. It is rare that the vegetation cause mechanical obstruction of the heart. What are some of the other pathological lesions that may be found? Multiple abscesses throughout the systemic circulation, in the brain, spleen, kidneys, etc.

Case 3 Fig. 4

CVS Practical Case 4 Mr. Lam, a 42 year old stock-broker collapsed at the Exchange floor. He was rushed to hospital and stayed in the Coronary Care Unit for three days before developing a fatal ventricular fibrillation. During the autopsy, it was found that the right coronary artery was totally occluded by a thrombus.

Case 4 Fig. 1

Question for Case 4 Fig. 1 Fig. 1 is a cross-section of a human heart. Indicate in Fig. 1, what you would expect to see at autopsy. The idea here is for you to draw on the picture what you would expect to see in a total occlusion of the right coronary artery. (The areas of perfusion of the coronary vessels). It is also important that you are able to orientate where is the anterior wall of the left ventricle. Finally remember that an occluded coronary artery gives rise to a transmural pattern of infarction.

The End.