Circulation
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The clinical and morphologic features of hypertrophic cardiomyopathy in 20 patients recognized as having cardiac disease in the first year of life are described. Fourteen of these 20 infants were initially suspected of having heart disease solely because a heart murmur was identified. However, the infants showed a variety of clinical findings, including signs of marked congestive heart failure (in the presence of non-dilated ventricular cavities and normal or increased left ventricular contractility) and substantial cardiac enlargement on chest radiograph. ⋯ Ventricular septal thickening was substantial in patients studied both before and after 6 months of age (mean 16 mm), indicating that in patients with hypertrophic cardiomyopathy, marked left ventricular hypertrophy may be present early in life and is probably congenital. The clinical course was variable in these patients, but the onset of marked congestive heart failure in the first year of life appeared to be an unfavorable prognostic sign; nine of the 11 infants with congestive heart failure died within the first year of life. In infants with hypertrophic cardiomyopathy, unlike older children and adults with this condition, sudden death was less common (two patients) than death due to progressive congestive heart failure.
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Hypertension and atherosclerotic coronary arterial obstruction frequently coexist in patients. However, the effect of increased aortic pressure on ischemic segmental dysfunction is not well understood. We studied the effects of aortic pressure increases on segmental left ventricular function during myocardial ischemia. ⋯ Increased aortic pressure in dogs without coronary occlusion produced reversible decreases in end-diastolic wall thickness, NET and LV dP/dt. Thus, the production of systemic hypertension with diastolic pressures of 110-120 mm Hg acutely or for 6 hours during evolving canine myocardial infarction does not appear to exert an important deleterious effect on myocardial oxygen supply and demand. However, 24 hours of mildly increased aortic pressure accentuates end-diastolic wall thinning in segments with paradoxic systolic motion and results in a failure of their return to control values at this period.
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The clinical entry characteristics and medical history of 142 resuscitated out-of-hospital cardiac arrest victims with coronary heart disease were studied in order to identify factors that affect their long-term survival. The cardiac arrest event was classified as being secondary to an acute myocardial infarction (AMI) in 44% (62 of 142), an ischemic event (IE) in 34% (49 of 142) and a primary arrhythmic event (PAE) in 22% (31 of 142). The majority of patients in all groups had a history of angina pectoris. ⋯ Covariate analysis for more than 40 variables indicates that a high-risk group included 22% (31 of 142) of the cardiac arrest victims had 1- and 2-year survival rates of 71% and 55%, respectively, and was characterized as having used digitalis before arrest, experiencing blood urea nitrogen elevation and pulmonary congestion during the hospitalization for the event, and classification of the cardiac arrest event as a PAE. A low-risk group comprised 78% (111 of 142) of the survivors and had 1- and 2-year survival rates of 85% and 69%, respectively. These data indicate that cardiac arrest due to coronary heart disease is secondary to several mechanisms related to subsequent survival.
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A new noninvasive method for determining arterial blood pressure is presented. Using a fast servo system, the pressure in the arm cuff is controlled so that the flow is maintained at a low value. ⋯ Mean arterial blood pressure was determined from the noninvasive recordings using the same mathematically valid procedure as was used for the invasive recordings. The deviation between the invasive and the noninvasive determinations of this measurement was -0.6 +/- 2.2 mm Hg (mean +/- SD) in 23 subjects.
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The effect of pulsatile flow during cardiopulmonary bypass on the hormonal stress response was studied in 26 patients. Thirteen had routine and 13 had pulsatile bypass with an average pulse pressure of 30 mm Hg. Plasma vasopressin levels were significantly elevated during bypass in both groups, but were lower with pulsation (66 +/- 11 vs 36.3 pg/ml, p less than 0.05). ⋯ There were no significant changes in renin activity in either group, but the increase after cardiopulmonary bypass was greater in the nonpulsatile group (2.0 +/- 0.7 vs 1.36 +/- 0.4 ng/ml/hr, NS). These data suggest that pulsatile flow significantly attenuates the vasopressin and catecholamine stress response to cardiopulmonary bypass. This may explain the increased flow requirements and better tissue perfusion and organ function and the decreased incidence of postoperative hypertension after bypass using pulsatile flow.