A very rare complication of the fibroid degeneration of the heart muscle is aneurysm of the heart wall. (Fig. 59.) The apex of the left ventricle is most commonly the site of the aneurysm and rupture occasionally occurs. Such an accident is rapidly fatal. In the arteriosclerotic process which occurs at the root of the aorta, the coronary arteries become involved both at the openings and along the courses of the vessels. A branch or branches or even one artery may become blocked as a result of obliterating endarteritis. The arteries of the heart are not terminal vessels but as a rule blocking of a large branch leads to anemic infarct. These areas become replaced by fibrous tissue which in the gross specimen appears as streaks of whitish or yellowish color in the musculature. Anemic infarcts may not occur. In such cases the anastomosis between branches of the coronary arteries is unusually free. Through arteriosclerosis of the coronary vessels extensive fibrous changes may occur that lead to a myocardial insufficiency with its attending symptoms--dyspnea, irregular and intermittent heart, gallop rhythm, edema, etc. One of the most distressing and dangerous results of sclerosis of the coronary arteries and of the root of the aorta is angina pectoris. While in almost every case of angina pectoris there is disease of the coronary arteries, the contrary does not hold true, for most extensive disease, even embolism, of the arteries is frequently found in persons who never suffered any attacks of pain. This symptom group is more common in males than in females and as a rule occurs only in adult life. "In men under thirty-five syphilitic aortitis is an important factor." (Osler.) Since the valuable experiments of Erlanger on heart block, considerable attention has been paid to lesions of the Y-shaped bundle of fibers, a bundle arising at the auriculoventricular node and extending to the two ventricles, known also as the auriculoventricular bundle of His. Interference with the transmission of impulses through this bundle gives rise to the symptom group known as the Stokes-Adams syndrome, which is characterized by: (a) slow pulse, (b) cerebral attacks--vertigo, syncope, transient apoplectiform and epileptiform seizures, (c) visible auricular impulses in the veins of the neck. Many of the cases which occur are in elderly people the subjects of arteriosclerosis. [Illustration: Fig. 60.--Large aneurysm of the aorta eroding the sternum. Death from rupture through the skin preceded by frequent small hemorrhages. (Milwaukee County Hospital.)] So far as we now know all cases of the Stokes-Adams syndrome are caused by heart block which is only another name for disease in the auriculoventricular bundle. Of interest here is the fact that besides gummata, ulcers, and other lesions of the bundle, definite arteriosclerotic changes have been found.