Practical pathology

by Aldred Scott Warthin

Before the valvular orifices are cut it is often expedient to test the adequacy of the valves by means of water or air. The hydrostatic test is employed to the best advantage in the case of the pulmonary and aortic valves, either by pouring water into the vessels, or by immersing the heart in water and then lifting it up quickly. In the case of the auriculoventricular valves the air-test is carried out by inserting the nozzle of a bellows through an opening made in the ventricular wall and noting the effect of blowing and suction. Graduated cones or balls may be used for more accurate measurement of the orifices, or they may be measured after they have been cut.

If sufficient care is exercised in cutting the valvular rings the incision can be carried between the flaps without injury to the latter. This is often desirable in cases of valvular lesion, endocarditis, etc. In such cases the valvular rings may be left uncut, the line of incision being broken by the auriculoventricular ring, when the mitral and tricuspid valves are concerned. The pulmonary and aortic rings may also be left uncut; the incisions are stopped at the rings, and then begun again in the vessel-walls beyond the valves.

When bacteriologic examinations of the heart-contents are to be made the wall of the auricles or right ventricles can be seared with a cautery and a pipette introduced through the seared area; or the heart can be opened with a sterile knife, care being taken not to introduce the fingers into the opening or to permit the entrance of water.

Excellent preparations for the museum or for demonstration purposes can be made by distending the heart with alcohol or formalin. Blood and blood-clots should first be washed out. When fixed the heart may be sectioned in various planes, leaving the segments attached by the epicardium posteriorly, or openings may be cut in the walls. A very good picture of hypertrophy and dilatation is obtained by making a transverse cut through the ventricles midway between apex and base. Alterations in the form and position of the ventricular septum are best seen by this method.

After the opening of the heart and the inspection of the orifices, valves and auricular and ventricular septa, the coronary vessels should be examined by transverse cuts, or opened by fine probe-pointed scissors, beginning at their origin in the aorta. The auricular septum should be carefully examined for possible defects. While this is being done the wall should not be put on the stretch, but should be lax. The auricular appendages should be cut open from the auricles and examined for thrombi, which are of not infrequent occurrence in them. The mouths of the coronary veins and the veins of Thebesius should be examined also. The cardiac muscle is examined by parallel, vertical or horizontal incisions. The papillary muscles should be cut longitudinally from apex to base. The cardiac plexus and the ganglion of Wrisberg should be examined before the heart is removed.

When the heart is in a state of rigor mortis the contraction should be made to pass away by kneading or by the application of heat, before the organ is opened, or before any measurements are taken. After the heart has been opened it may be removed for weighing.

The heart may be removed first and then opened outside of the body. The organ is grasped in the left hand and lifted vertically and upward toward the head as far as possible, putting all of the attachments on the stretch. The vessels are then cut from below upward, first the inferior vena cava, then the pulmonary veins, the superior vena cava, pulmonary artery and lastly the aorta. (See Fig. [39].) The vessels should be cut as closely as possible to their exits through the pericardium, and care must be taken to get out the auricles entire.

Fig. 39.—Removal of Heart. Dark line shows incision through vessels. (After Nauwerck.)

After removal from the body the heart is placed upon the board with its anterior surface up, and the apex toward the operator. It may then be opened by the same method given above, by inserting the point of the brain-knife into the left ventricle just to the left of the septum, and cutting first the wall of the left ventricle along its left border as far as the mitral ring, exploring the mitral orifice, and then cutting it and the auricular wall into the upper left pulmonary vein with the long shears. The right ventricle, right auricle, pulmonary artery and finally the aorta are opened in succession, using the enterotome for all cuts except the first opening of the ventricle. The first incisions into the ventricles can be made very conveniently by holding the heart vertically with apex up, and the ventricle to be opened toward the prosector. The brain-knife is held vertically and its point inserted into the ventricle, just to the right or left of the septum, according to the ventricle to be opened, then carried across the cavity and pushed through the ventricular wall below the auriculoventricular ring, and the wall is then cut toward the apex. The remaining incisions are most easily made with the enterotome when the heart is held flat on the board with its anterior surface up. When the heart is opened outside of the body the Virchow method of opening in the direction of the blood-stream may also be used. (See below.)