Circulation
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This investigation presents additional evidence for the hemodynamic influence of intracardiac anomalies on the development of the aortic arch, based on measurements of different parts of the great vessels. Criteria are given to define the normal aortic arch and the different anomalies of the aortic arch, such as interruption, atresia, tubular hypoplasia, hypoplasia, abnormal long segment and juxtaductal coarctation. Two types of of malignment venentricular septal defects are described to illustrate how prenatal intracardiac flow disturbances can account for various aortic arch patterns. An explanation is proposed as to how reduced blood flow through the embryonic preductal aorta may contribute to the pathogenesis of all dimensional anomalies of the aortic arch.
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A four-year-old boy with a myocardial infarct and total occlusion of the right coronary and the left anterior descending coronary arteries due to mucocoutaneous lymphnode syndrome (MCLS). confirmed by selective coronary arteriography, underwent successful double aortocoronary bypass grafting. Patency of the grafts was demonstrated by graft angiography and the improvement of the contractile pattern of the left ventricle was reflected by the increase in ejection fraction from 0.45 to 0.61. ⋯ However, there are unanswered questions regarding the fate of the saphenous vein graft in relation to the growth of a child. Long-term clinical and angiographic follow-ups are mandatory to determine the significance of this mode of surgical treatment for the sequela of MCLS.
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Echocardiography was performed in 62 patients--20 with truncus arteriosus, 14 with tetralogy of Fallot, and 28 with pulmonary atresia with ventricular septal defect. Features common in all three groups were: large single systemic arterial trunk overriding the ventricular septum, mitral-semilunar continuity, large right ventricular dimension, and normal septal motion. ⋯ Left atrial dimension was measured in 55 patients and was normal or small in 41 patients and large in 14 patients. Our observations indicate that left atrial dimension provides a good index of pulmonary flow and can help differentiate those patients with increased pulmonary flow and can help differentiate those patients with increased pulmonary flow (truncus arteriosus) from those patients with reduced pulmonary flow (tetralogy of Fallot and pulmonary atresia with associated ventricular septal defect).
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To examine the role of angiotensin II in the maintenance of blood pressure and the control of aldosterone secretion in man, eight normal subjects were studied on a tilt table in sodium replete and sodium depleted states prior to and subsequent to the intravenous infusion of an angiotensin converting enzyme inhibitor (CEI). In both the sodium replete or sodium depleted state, upright tilting resulted in an increase in heart rate and a narrowing of pulse pressure. None of the sodium replete or depleted subjects fainted. ⋯ In supine subjects, after the administration of converting enzyme inhibitor, plasma renin activity rose but plasma aldosterone concentration fell. In sodium depleted subjects, after the administration of CEI, aldosterone fell to a level significantly lower than that in supine controls and to a level no different from the supine sodium replete subject. These results indicate that angiotensin II is essential for blood pressure maintenance in sodium depleted individuals, that angiotensin II exerts a direct feedback control on renin secretion, and that angiotensin II is the primary stimulus to aldosterone secretion in response to both sodium depletion and to posture.
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Comparative Study
Lung water and urea indicator dilution studies in cardiac surgery patients. Comparisons of measurements in aortocoronary bypass and mitral valve replacement.
We measured transpulmonary indicator dilution curves of 51Cr-erythrocytes, 125I-albumin, 14C-urea, and 3H-water before and six and 24 hours after operation in seven patients undergoing aortocoronary bypass (ACB) and eight patients undergoing mitral valve replacement (MVR). We calculated cardiac output (CO), extravascular lung water (EVLW), the difference between 125I-albumin and 51Cr-erythrocyte distribution volumes (EV albumin), the difference between 14C-urea and 51Cr-erythrocyte distribution volumes (EV urea) and 14C-urea extraction (E) and permeability -surface ares (PS) products. Comparisons between 16 ACB studies and 17 MVR studies showed the MVR group to have a higher EVLW (P less than 0.01). ⋯ We conclude that patients with mitral valve disease have an increased distribution volume and E for urea, probably due to hemodynamic changes but possibly due to increased vascular permeability. Extravascular lung water decreases after cardiac surgery regardless of the type of operation. A single intravascular indicator is adequate for estimating extravascular lung water in humans.