David J. Fisher

University of California, San Francisco, San Francisco, California, United States

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Publications (4)9.21 Total impact

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    ABSTRACT: Subaortic stenosis is rarely mentioned as a lesion that may be associated with a ventricular septal defect. We have encountered 4 patients with discrete subaortic stenosis adjacent to a ventricular septal defect, all of whom posed significant problems in diagnosis. In all 4 patients the subaortic stenosis was silent clinically and in 3 cases the obstruction was also not detected at the initial cardiac catheterization and angiocardiography. In the latter 3 cases, after surgical closure of the ventricular septal defect, there was a loud systolic murmur initially thought to be due to a small residual ventricular septal defect. In time, the clinical findings became more typical of isolated subaortic stenosis. In each of these cases the obstruction was verified at cardiac catheterization with peak systolic pressure gradients of 145, 45, and 70 mmHg. During reoperation, a discrete subaortic shelf was found opposite the patch used to close the ventricular septal defect. In the 4th case, the subaortic stenosis was unsuspected by clinical evaluation but was diagnosed by echocardiography as well as at cardiac catheterization, and both the ventricular septal defect and subaortic stenosis were corrected at the initial operation. A discrete subaortic shelf situated adjacent to a ventricular septal defect may be "silent," producing minimal, if any, pressure gradient and may pose diagnostic difficulties. Failure to recognize such a shelf and to remove it at the time of surgical closure of the ventricular septal defect, may result in the creation of a severe subaortic obstruction.
    No preview · Article · Feb 1982 · Pediatric Cardiology
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    David J Fisher · Michael A Heymann · Abraham M Rudolph
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    ABSTRACT: We measured blood flow to the myocardium of the left ventricular free wall, and blood glucose, lactate, pyruvate, and oxygen concentrations simultaneously in the aorta and coronary sinus 13 times in seven previously instrumented newborn sheep, 4 to 25 days after birth. We calculated arteriovenous difference and consumption of oxygen, glucose, lactate, and pyruvate by the newborn myocardium. Results were compared with recently obtained measurements in the myocardium of fetal and adult sheep (6). Myocardial consumption of oxygen in the newborn (577 +/- 38 microM.min-1.100 g LV-1) was higher than in either the fetuses or the adults. This was associated with a greater myocardial blood flow (201 +/- 21 mm.min-1.100 g LV-1) in the newborns. However, the increased myocardial oxygen consumption in the newborns was commensurate with their increased cardiac work as compared with both the fetuses and adults. Although there is an abrupt postnatal increase in arterial glucose concentration, there was no significant difference in either the myocardial consumption of glucose or the contribution of glucose to the total myocardial energy supply among fetal, newborn or adult sheep. Postnatal decreases in myocardial consumption of lactate and pyruvate are not compensated for by an increase in glucose consumption. In newborn sheep, carbohydrates including glucose, lactate, and pyruvate supply the substrate for no more than approximately one-fourth of the total myocardial energy demands (carbohydrate/oxygen quotient was 0.26).
    Preview · Article · Jun 1981 · Pediatric Research
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    David J. Fisher · Abraham M. Rudolph · Michael A. Heymann
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    ABSTRACT: Although fetal arterial levels of oxygen and glucose are less than half adult levels there is no information about tissue extraction of these substrates in the intact fetus. We studied fetal myocardial extraction of oxygen, glucose, lactate and pyruvate in 12 fetal lambs in utero, 1-4 days post-op. We placed catheters in inferior vena cava, carotid artery (CA), and coronary sinus (CS) via the hemiazygous vein. From simultaneously withdrawn blood, CA and CS O2 content, blood glucose, lactate and pyruvate were measured. Myocardial blood flow (cc/min/100g) of left ventricle (MBF/min/100gmLV) was calculated by the nuclide-labelled microsphere method. Myocardial extraction of substrate/min/100g of left ventricle (MV/min/100gmLV) was calculated as CA minus CS level of each substrate (Δ-AV) times MBF/min/100gmLV. MBF/min/100gmLV was 166±19 (mean±SEM), twice the value for normal adult humans and dogs. CA levels of O2, glucose, lactate and pyruvate (uM/L) were 3244±199, 1069±122, 2120±327 and 117±14, respectively. Δ-AV for O2, glucose, lactate and pyruvate (uM/L) were 2117±100, 99±18, 524±88, and 49±9, half the value of normal adults. MV/min/100gmLV (uM/L) for O2, glucose, lactate and pyruvate were 333±30, 18±4, 76±16, and 7±2, respectively, equal to values for normal adults. We conclude that fetal myocardial extraction/min/100gmLV of O2 and glucose are equal to values obtained from healthy adults, despite the lower arterial levels of O2 and glucose present in utero. This is accomplished by higher fetal myocardial blood flow.
    Preview · Article · Apr 1978 · Pediatric Research

  • No preview · Article · Feb 1978 · The American Journal of Cardiology