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Necrotizing arteritis

No

a Grade 4 plexiform lesions are now thought to represent the aftermath of necrotizing arteritis and microaneurysm formation and, hence, follow rather than precede grade 5 and 6 lesions. Adapted with permission from Edwards (63).

a Grade 4 plexiform lesions are now thought to represent the aftermath of necrotizing arteritis and microaneurysm formation and, hence, follow rather than precede grade 5 and 6 lesions. Adapted with permission from Edwards (63).

artery during valve surgery. Accordingly, the myocardial sections recommended for cases of valvular heart disease are the same as those for ischemic heart disease, particularly if there is a valvular vegetation, valvular prosthesis, or history of sudden death.

Additional recommendations for specific valvular lesions are listed in Part II of this book.

CARDIOMYOPATHIES For most cases of dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and hypertrophic cardiomyopathy, the heart should be dissected by the short-axis method. In contrast, the four chamber method is ideal for demonstrating biatrial dilatation in the eosinophilic and noneosinophilic forms of restrictive cardiomyopathy. Occasionally, it can also be used for dilated or hypertrophic cardiomyopathy (see Fig. 3-3B,C). The long-axis method of dissection is useful for demonstrating the anatomic substrate for left ventricular outflow tract obstruction in some patients with hyper-trophic cardiomyopathy.

The heart from any adult with suspected cardiomyopathy should be evaluated for coexistent coronary atherosclerosis. For dilated cardiomyopathy in adults, an iron stain is recommended for the evaluation of possible hemochromatosis, and an amyloid stain is suggested for cases with suspected hyper-trophic cardiomyopathy. (For macroscopic staining methods, see Chapter 14.) Diffusely vacuolated myocytes may be indicative of an underlying storage disease, such as Fabry's disease; transmission electron microscopy is indicated in such cases.

Additional recommendations for specific types of cardiomy-opathy are listed in Part II of this book.

CONGENITAL HEART DISEASE The evaluation should include study of the underlying malformation, its secondary effects on the heart and lungs, and review of diagnostic or therapeutic procedures and their effects or complications (63). Chronic lesions such as aortic root dilatation (with conotruncal anomalies) or myxomatous valves (with single functional ventricles), in operated patients who have survived into adulthood, may also be encountered at autopsy.

Detailed descriptions of the specific forms of congenital heart disease can be found in Part II of this book. Synonyms abound for cardiovascular anomalies, and these are listed in Appendix 3-2, as well as with each individual malformation in Part II. For cardiac anatomy and for congenital cardiac anomalies, Anglicized terms rather than Latin names are currently preferred, and these are listed in Appendix 3-3. Common epo-nyms for various surgical procedures applied to malformed hearts, and their explanations are supplied in Appendix 3-4. In Appendix 3-5, a two-page form is provided that can be used during the autopsy evaluation of complex cases of congenital heart disease (63-65).

In general, the thoracic organs should be removed en bloc but if the vascular connections are normal, the tracheobron-chial tree, lungs, and esophagus can be removed from the heart. Section from the upper and lower lobes of both lungs should be evaluated for pneumonia and hypertensive pulmonary vascular disease. Note that the modified Heath-Edwards classification of plexogenic pulmonary hypertension is applicable only for subjects with congenital left-to-right shunts (see Table 3-4). In operated patients, the lesions of pulmonary venous hypertension are more common than plexogenic disease.

The major epicardial coronary arteries should be examined for anomalies in origin and distribution and for obstruction, especially if operative procedures have been performed nearby. Cardiomegaly is a common feature; even years after surgical repair of congenital heart disease, residual ventricular hypertrophy and dilatation may be striking. Asymmetric septal hypertrophy in conotruncal anomalies should not be misinterpreted as coexistent hypertrophic cardiomyopathy.

Congenitally malformed hearts may be opened by the inflow-outflow method but in postoperative cases, the short-axis method is best (see Fig. 3-2D). In selected circumstances (see Fig. 3-4D and 3-6), the four-chamber, long-axis, base-of-heart, and window methods are also useful (10). In general, microscopic sections should be taken from both ventricles for the evaluation of fibrosis and recent ischemic injury, particularly in the subendocardial region of hypertrophied hearts.

UNEXPLAINED SUDDEN DEATH The coronary arteries should be examined carefully throughout their length, to document any anomalies or obstructions, including ostial flaps. Hearts with appreciable ischemic, valvular, cardiomyopathy, or congenital lesions should be dissected as described earlier.

If the heart appears grossly normal, at least four slides should be taken for microscopy from the left ventricle, and two from the right ventricle. If no myocarditis or acute myocardial ischemia is detected microscopically, the cardiac condution system should be evaluated as described earlier in this chapter. Though rare, mesothelioma of the AV node or sarcoidosis of the AV node or AV (His) bundle may cause sudden death. In some fatal arrhythmic disorders, such as the long QT syndrome, the heart may be normal grossly and microscopically (66). This syndrome has been implicated in some incidents of drowning and near drowning (67). See also under "Death, sudden unexpected, ..." in Part II of this book.

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