Controversial areas in cardiovascular pathology

Controversial areas in cardiovascular pathology

Pathology (2014) 46(S1), pp. S19–S22 Forensic Pathology UPSIDE-DOWN DEATH – THE PATHOPHYSIOLOGY OF INVERSION ARRYTHMOGENIC RIGHT VENTRICULAR CARDIO...

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Pathology (2014) 46(S1), pp. S19–S22

Forensic Pathology

UPSIDE-DOWN DEATH – THE PATHOPHYSIOLOGY OF INVERSION

ARRYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY

Kirsty Andrews Medlab Central, Palmerston North, New Zealand

Mary N. Sheppard Department of Histopathology, Royal Brompton Hospital and Harefield NHS Foundation Trust, London, United Kingdom

Historically, deaths occurring in a head-down position were generally associated with inverted suspension inflicted upon the victim as a form of torture. In the current day, deaths occurring due to an inverted body position are rare and are usually the result of freak accidents which often attract media attention due to the unusual nature of the death. Occasionally an element of inverted suspension is present in deaths occurring in motor vehicle incidents when the vehicle rolls, coming to rest on its roof with the unconscious victim left suspended upside-down by the seat belt. Human physiology has evolved to work in combination with gravity and the effects of hanging upside down for prolonged periods are poorly understood. I will review deaths associated with the head-down position and the underlying pathophysiology of inversion leading to death.

CONTROVERSIAL AREAS IN CARDIOVASCULAR PATHOLOGY Mary N. Sheppard Department of Histopathology, Royal Brompton Hospital and Harefield NHS Foundation Trust, London, United Kingdom Key points: 1. Anomalous coronary arteries are a cause of sudden death, usually with distribution between the great vessels. Death with exertion is common. 2. Beware normal variants of origin or distribution of coronary arteries. 3. Bridging is only diagnosed if the left anterior coronary artery is 5 mm deep and 15–20 mm long within the myocardium. 4. High take off is only diagnosed 20 mm above the sinutubular junction with narrowing of the ostium. 5. Fibromuscular dysplasia is very rare. Can be genetic or acquired. Cocaine use must be considered. 6. Coronary artery dissection occurs in young pregnant or postpartum females. 7. While coronary artery spasm is an established event angiographically, pathologists cannot diagnose it. When there is regional infarction with normal coronary arteries it must be considered. 8. Kounis syndrome (KS) or allergic angina/myocardial infarction. Allergic acute coronary syndrome (ACS) is still questioned. Two subtypes have been described: type I, which occurs in patients without predisposing factors for coronary artery disease and is caused by coronary artery spasm, and type II, which occurs in patients with angiographic evidence of coronary disease when the allergic events induce plaque erosion or rupture. Autopsy in the context of these abnormalities means meticulous examination of the coronary arteries. Print ISSN 0031-3025/Online ISSN 1465-3931

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Key points: 1. A cause of arrhythmias and sudden death. 2. Usually in young males during exertion. 3. Transmural fat macroscopically with thinning and scarring in both ventricles. 4. Heart may be macroscopically normal. 5. Microscopically transmural fat and fibrosis with focal inflammation usually on epicardial surface of right and left ventricle. Fat infiltration alone is not pathological. 6. Histological changes may be focal in the right ventricular outflow tract. 7. Be wary and do not diagnose in obesity, coronary artery disease and in the elderly. The classification of cardiomyopathies is now based more on genetic and pathogenetic mechanisms. Gene mutations distinguish cytoskeleton (cytoskeletalopathies, e.g. DCM or ARVC), sarcomeric (sarcomyopathies as in HCM and RCM) and ion channel (channelopathies, e.g., long or short QT syndrome and Brugada’s syndrome) cardiomyopathies. Cardiomyopathies, previously considered single entities, are the result of mutations in different genes. Different mutations in the same gene may be the cause of different clinical entities. Large phenotypic and genetic heterogeneity exists. Arrhythmogenic cardiomyopathy (ARVC) was the last cardiomyopathy to be described back in the 1990 s and its pathogenesis remains controversial both pathologically and genetically. Both the right and left ventricle can be involved with transmural fat infiltration and fibrosis.

RIGHT VENTRICULAR PATHOLOGY IN PULMONARY THROMBOEMBOLISM AND ATHLETES Johan Duflou Department of Forensic Medicine Sydney, Glebe, NSW, Australia Although infrequently observed during routine histologic sampling of the heart at autopsy, right ventricular inflammation is commonly seen in the right ventricular outflow tract in persons dying of pulmonary thromboembolic disease. The lesions are characterised by the presence of a mixed inflammatory cell infiltrate with focal necrosis and occasionally areas of fibrosis and fat infiltration. Very infrequently, these lesions may also be seen in other parts of the right ventricle, and occasionally in the left ventricular myocardium. When taken together with the not infrequent biochemical findings of raised troponin and B-type natriuretic peptide levels in these cases, a strong case can be made that these lesions are the result of right ventricular strain with acute outflow tract dilatation, and not primarily the result of right ventricular ischaemia or right sided myocarditis, as hypothesised in the past.

2014 Royal College of Pathologists of Australasia

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