Examination of the Myocardium in Ischemic Heart Disease

In the presence or absence of acute or healed myocardial infarction, the myocardium is best examined by slicing the ventricles in a manner similar to a loaf of bread. To evaluate the specimen, a series of short-axis cuts are made through the ventricles from apex to base (Figure 2.2.1.5A). This method is best accomplished using a long, sharp knife on the intact fixed specimen following examination of the coronary arteries. With the anterior aspect of the heart downward (against the cutting board), the cuts are made parallel to the posterior atrioventricular sulcus at 1- to 1.5-cm intervals from the apex of the heart to a point approximately 2 cm caudal to the sulcus or up to the mid-portion of the papillary muscles of the left ventricle.

The result is a series of cross-sections through the ventricles, including papillary muscles with the atrioventricular valve apparatus left intact in the remainder of the specimen. The location and extent of the infarct is noted. Locations may be stated using terms relating to the

Papillary Muscle Infarct

Figure 2.2.1.5 The location and extent of myocardial infarction must be indicated by the size, that is, how much of the base to apex is infarcted: basal one third, and/or middle one third, and/or apical one third or more than one third from base to apex. The diagram in (A) shows a long axis view of the heart with regional nomenclature. (B) The location of the myocardial infarction in the left ventricle must also indicate the wall in which the infarction occurred: anterior, posterior, lateral, septal, or any combination of these. This diagram illustrates a short-axis view through the basal, middle, and apical portions of the right and left ventricles. (Ao = aorta; Ant = anterior; ALPM = anterolateral papillary muscle; AML = anterior mitral leaflet; Inf = inferior; LA = left atrium; LV = left ventricle; Mid = middle; PML = posterior mitral leaflet; PMPM = posteromedial papillary muscle; Post = posterior; RV = right ventricle; VS = ventricular septum) (Modified from Edwards, W.D., Tajik, A.J., and Seward, J.B., Standardized nomenclature and anatomic basis for regional tomographic analysis of the heart, Mayo Clin. Proc, 56:479, 1981. From Virmani, R., Ursell, P.C., and Fenoglio, J.J., Examination of the heart, in Virmani, R., Atkinson, J.B., and Fenoglio, J.J., Eds., Cardiovascular Pathology, W.B. Saunders, Philadelphia, 1991, pp 1-20. With permission.)

Figure 2.2.1.5 The location and extent of myocardial infarction must be indicated by the size, that is, how much of the base to apex is infarcted: basal one third, and/or middle one third, and/or apical one third or more than one third from base to apex. The diagram in (A) shows a long axis view of the heart with regional nomenclature. (B) The location of the myocardial infarction in the left ventricle must also indicate the wall in which the infarction occurred: anterior, posterior, lateral, septal, or any combination of these. This diagram illustrates a short-axis view through the basal, middle, and apical portions of the right and left ventricles. (Ao = aorta; Ant = anterior; ALPM = anterolateral papillary muscle; AML = anterior mitral leaflet; Inf = inferior; LA = left atrium; LV = left ventricle; Mid = middle; PML = posterior mitral leaflet; PMPM = posteromedial papillary muscle; Post = posterior; RV = right ventricle; VS = ventricular septum) (Modified from Edwards, W.D., Tajik, A.J., and Seward, J.B., Standardized nomenclature and anatomic basis for regional tomographic analysis of the heart, Mayo Clin. Proc, 56:479, 1981. From Virmani, R., Ursell, P.C., and Fenoglio, J.J., Examination of the heart, in Virmani, R., Atkinson, J.B., and Fenoglio, J.J., Eds., Cardiovascular Pathology, W.B. Saunders, Philadelphia, 1991, pp 1-20. With permission.)

standard anatomic terms of reference (e.g., anteroseptal, posterolateral). The extent of infarction may be described in terms of circumference of the ventricle involved12-14 and longitudinal portion of the ventricle involved (e.g., basal third, middle third, apical third) (Figure 2.2.1.5 A and B).

The distribution within the wall is also described (e.g., transmural or subendocardial; transmural when the infarct extends from the endocardium to the epicardium, and subendocardial when <50% of the left ventricular wall is infarcted). The gross pathologic appearance of the myocardium serves as a relatively good index as to the age of the infarct but must be confirmed by histologic examination. Even if infarction cannot be identified grossly, it is important to section the myocardium in the distribution of the severely diseased coronary arteries more extensively.

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