Nonrheumatic calcific aortic stenosis

Abstract

1. 1. A study was made of fifteen cases of calcific aortic stenosis in which detailed pathologic examination (previously reported) had shown that the lesion was nonrheumatic. In four of the cases there was an associated syphilitic aortitis. 2. 2. While in most cases of calcific aortic stenosis there is considerable evidence that the etiology of the lesion is rheumatic, this evidence does not preclude the existence of a nonrheumatic form of the disease. 3. 3. The cases in our series fell into three groups. The first, consisting of six cases, was characterized by the development of left- and right-sided heart failure. The history of these patients revealed the typical symptoms of calcific aortic stenosis, including angina pectoris, dizziness, and syncope. Electrocardiograms frequently showed varying degrees of heart block, such as bundle branch block and intraventricular conduction disturbances, and abnormalities of the T-waves and RST transitions. In occasional cases death occurred suddenly. In the second group, consisting of five cases, the valvular lesion was discovered accidentally in patients who died of some unrelated disease. Neither the characteristic symptoms of the valvular abnormality nor evidences of heart failure were present. The third group, containing four cases, resembled the first, both in the occurrence of cardiac failure and in the appearance of the other characteristic symptoms. These cases were segregated because there was associated syphilitic aortitis and aortic valvular disease. 1. 4. Seven cases typifying these three groups were presented in moderate detail. 2. 5. The occurrence and pathogenesis of angina pectoris, conduction disturbances, dizziness and syncope, and sudden death were discussed. 2.1. A. Angina pectoris is believed to be caused by myocardial ischemia due to coronary insufficiency. When the patient is at rest, coronary insufficiency is due partly to the increased demand for blood made by a greatly hypertrophied heart, and partly to the diminished coronary flow. The coronary flow is reduced by the increased peripheral coronary resistance resulting from the extremely high systolic pressure within the left ventricle. During exertion the coronary insufficiency becomes more marked. Verification of the existence of coronary insufficiency in these cases is furnished by the occasional instances of myocardial infarction without acute coronary occlusion and by the electrocardiograms, which may resemble those of coronary occlusion. 2.2. B. The conduction disturbances, as well as the changes in T-waves and RST transitions, were similarly explained as being caused by myocardial ischemia due to coronary insufficiency. Occasionally, heart block is due to extension of the calcific process to the septum, but the nature of some of the conduction disturbances, their occurrence in some patients on effort, and their transience suggested that they were due predominantly to myocardial ischemia. 2.3. C. Dizziness and syncope occur almost always on effort. They are thought to be due to cerebral ischemia. The already high left intraventricular pressure necessary to compensate for extreme aortic stenosis can be further elevated only with difficulty when there is a demand for increased cerebral blood flow. Occasionally, a hypersensitive carotid sinus also may play a role. 2.4. D. Sudden death in this disease may have various causes. It may be due to coronary thrombosis, or to myocardial infarction resulting from severe ischemia without acute occlusion (i.e., from coronary insufficiency). Occasionally it may be due to severe cerebral ischemia, obstructing thrombi on the stenotic aortic valve, a hypersensitive carotid sinus reflex, cardiac standstill, or ventricular fibrillation. 3. 6. A summary was given of the means of diagnosing calcific aortic stenosis, of differentiating it from the diseases with which it is ordinarily confused, and of distinguishing the rheumatic from the nonrheumatic cases.