Where a full thickness infarct has occurred with replacement of myocardium by fibrous tissue, this inert portion of the ventricular wall cannot take part in concentric contraction and herniates outwards during ventricular systole. This localized disturbance of ventricular contraction after acute myocardial infarction is seen not only in large ventricular aneurysms but alsowith smaller full thickness infarcts (minor aneurysms) that have not caused a definite protrusion of the external surface of the heart. In this paper the range of localized disorders of ventricular contraction has been studied clinically, radiologically, at operation, and at necropsy. In diagnosis, special emphasis has been placed on abnormalities of the cardiac impulse, readily appreciated at the bedside, and on the information obtained from detailed fluoroscopy.The prognosis after acute myocardial infarction depends not only on the possibility of a further infarct occurring, but also on the degree of damage that the infarct has inflicted on the ventricles as an efficient pump. The influence of major and minor aneurysms on prognosis following myocardial infarction has been examined.
SUBJECTS AND METHODSThe 39 patients studied fell into 2 main groups.There were 13 patients in whom the diagnosis of ventricular aneurysm was confirmed either at operation or at necropsy. The second group consisted of 26 patients in whom the diagnosis of ventricular aneurysm was made on clinical and radiological grounds alone. Of these 39 patients, 18 were diagnosed as having a ventricular aneurysm during admission to Hammersmith Hospital in a series of 112 consecutive patients treated in the Acute Coronary Care Unit
Oxygen affinity of blood was measured in 16 patients (nonsmokers) without anemia and with clinical evidence of low cardiac output. Of these patients, 12 were catheterized and showed an arteriovenous oxygen concentration difference across the lungs greater than 5 ml/100 ml. The partial pressure of oxygen required to half-saturate their blood with oxygen (P 50 ) averaged 29.4 mm Hg (SD ± 1.9). Blood from normal subjects (nonsmokers) had an average P.-l0 of 27.3 mm Hg (SD ± 0.9). The decreased oxygen affinity found in blood of patients with low levels of cardiac output is considered as a compensatory adjustment to poor tissue blood flow, promoting the diffusion of oxygen from blood in tissue capillaries to intracellular sites of utilization.ADDITIONAL KEY WORDS compensation for tissue hypoxia oxygen dissociation curve
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.