Hans U. Wessel

Coarctation of the Aorta in Infancy

Material from 78 infants with coarctation and congestive heart failure during the first 6 months of life was reviewed. Three fourths of these infants had combined aortic lesions, that is, coarctation, a narrow constrictive zone of stenosis, and tubular hypoplasia of the transverse arch, a proximal, long, uniformly narrow segment.It was the purpose of this study (1) to distinguish coarctation of the aorta from tubular hypoplasia by using pathologic and angiographic measurements, (2) to assess the relationship of these two entities and additional shunting cardiac defects with the occurrence of congestive heart failure in infancy, and (3) to evaluate the optimal therapeutic approach for symptomatic infants with coarctation.It was found that (1) coarctation of the aorta as an isolated anomaly is a relatively uncommon cause of congestive heart failure in infancy. In contrast, coarctation associated with tubular hypoplasia of the transverse arch or with additional cardiac defects is frequently associated with severe congestive heart failure. It was found also (2) that surgical management is far more successful than medical management alone in symptomatic infants with coarctation of the aorta and associated significant cardiac defects.

Continuous determination of oxygen uptake in sedated infants and children during cardiac catheterization

Abstract The variation of oxygen uptake during cardiac catheterization was studied in 98 sedated infants and children by a flow-through technic which requires no direct patient contact or cooperation, does not interfere with cardiac catheterization, and permits continuous on-line determination of oxygen uptake. During sedated sleep O2 uptake averaged 102 ± 51 ml./min. or 154 ± 26 ml./min. per M2. For this limited sample population O2 uptake was linearly related to body surface area, age, height and weight. O2 uptake per M2 decreased with increasing body surface area and was relatively greater in underweight children. The awake state and activity resulted in significant increases of O2 uptake even in restrained children. The method provides accurate measurements of O2 uptake and can be used routinely in infants.

RESPIRATORY AND CARDIOVASCULAR FUNCTION IN PATIENTS WITH SEVERE PULMONARY HYPERTENSION.

HEATH and Whitaker 1 applied the term hypertensive pulmonary vascular disease to patients with chronic, severe pulmonary hypertension. They emphasized that this disease is a distinct clinicopathologic entity with uniform clinical features and characteristic morphologic changes of the pulmonary arteries and arterioles irrespective of the etiology of the hypertension. The vascular changes indicate restriction of the pulmonary vascular bed, which may alter pulmonary gas exchange. This study of the respiratory physiology of such patients was undertaken to determine if the uniform clinical picture could in part result from some common, specific pathophysiologic mechanism.

Automatic computation of the area under indicator dilution curves

A method is described which can be utilized to automate calculation of the area under dilution curves. Based on this method, an analog computer has been designed for on-line computation of dilution curve areas. The circuitry and mode of operation are described, and the limitations of the instrument are discussed. Two semiautomatic methods of dilution-curve area calculation are demonstrated.

Mitral insufficiency following experimental papillary muscle infarction.

Abstract Nineteen dogs which survived occlusion of the left circumflex coronary artery with infarction and scarring of the posterior papillary muscle and adjacent left ventricle were studied by cineangiography 260 to 341 days after occlusion. Development of slight to moderate mitral-valve regurgitation was observed in 4 of the 19. Angiograms showed varying degrees of stiffness and rigidity of the posterior lateral wall of the left ventricle. There was no indication of heart failure. Autopsy studies revealed a dense fibrous scar involving 50 to 100 per cent of the posterior papillary muscle and varying portions of the adjacent left ventricular wall, with no involvement of the mitral-valve leaflets or chordae tendineae. The combination of a papillary muscle and left ventricular wall scar acted together to produce mitral-valve regurgitation in 4 of 19 animals.

Variants of Cardiopulmonary Manifestations of Manson's Schistosomiasis: Report of Two Cases

Excerpt Chronic visceral schistosomiasis may lead to two distinct cardiopulmonary sequelae: [1] cor pulmonale due to obstructive hypertensive pulmonary vascular disease and [2] a cyanotic syndrome ...

THE EFFECT OF BREATH BY BREATH VARIATIONS OF FRC ON THE MEASUREMENT OF O2 AND CO2 GAS EXCHANGE AT THE MOUTH.

With the availability of rapid response multiple gas analyzers, breath-by-breath analysis of Ventilation and pulmonary gas exchange has become practical. Virtually without exception the methods proposed for measurement of gas exchange over single respiratory cycles are based on applications of steady state equations. These equations assume constant end-expiratory lung volume (FRC), i.e. no net N2 exchange over the measurement period (VIN2 = V^). Since this is clearly not the case we have determined the magnitude of breath-bybreath FRC changes, AFRC, and examined the effect of AFRC on the measurement of 02 and CÜ2 gas exchange during air breathing.

COMPUTERGESTEUERTE BELASTUNGSUNTERSUCHUNGEN IN DER KINDERKARDIOLOGIE: ATEMZUG-ZU-ATEMZUG ANALYSE VON VENTILATION UND ALVEOLÄREM GASAUSTAUSCH

During the last seven years we have developed an Integrated, computerized System for breath-by-breath analysis of Ventilation and pulmonary gas exchange at rest and during exercise. The System can be utilized for patient studies in the setting of a clinical laboratory and was designed to integrate the following functions: 1) Gas flow calibration 2) Gas concentration calibration 3) Analog data acquisition: gas flow and concentrations 4) Direct A/D conversion of analog data 5) Off-line data analysis of breath-by-breath Information 6) Data Output: Breath-by-breath and summary data 7) Generation of patient data base 8) Data evaluation: Graphics (drum plot) , statistical analysis Evaluation of breath— by-breath Ventilation and gas exchange is based on analysis of the following source data measured continuously at the mouth: inspired gas flow C^i ) , expired gas flow (VE) » and the f ractional concentrations of N2, 02, and C02. Our approach is based on the premise that a single breath represents a non-steadystate. Specifically, there are breath-by-breath variations of end-expiratory lung volume (FRC) , i.e. VI VE / VQ2 Vco2· Since the conventional steadystate gas uptake equations assume constant FRC over the measurement period they are invalid for single breath analysis. We have utilized uptake equations which make no assumptions about the relationship between inspired and expired volume. The equations are valid under non-steadystate conditions and thus meet the requirements for single breath analysis. In a gener al form the uptake of gas at the mouth M for breath n, V^n) is given by:

Mass spectrometer for multiple respiratory gas analysis.

The vacuum System, inlet, and Output analog circuitry of a two-channel time-of-flight mass Spectrometer (Model MA-I, Bendix Corp., Scientific Instruments Division, Cincinnati, Ohio) were redesigned to develop a respiratory gas analyzer with: 1) capability to analyze any gas over a mass ränge from 2—50 amu, 2) a 10—90% response time of ms 3) non-]inearity not exceeding ± l %>, 4) a Signal to noise ratio of ^> 100 : l, 5) a gas sample of 10cc/min., 6) simultaneous analysis of six gases, and 7) simplified reliable Operation for routine clinical application. A new, simple two-stage inlet (sampling needle valve and micrometer leak valve) provides fast response and is insensitive to water vapour and viscosity changes of the sampled gas. Six gas multi-channel Operation is achieved by time division multiplexing of two analog anodes through a variable gain electrometer amplifier.

Design of a centralized electrocardiographic and vectorcardiographic system

Abstract A centralized system for recording standard 12-lead electrocardiograms and vectorcardiograms is described. Multiple simultaneous signals are obtained from the patient by means of buffer amplifiers which minimize the effect of differences in skin resistance at the electrodes on resistance networks. Rightleg driving is employed to reduce common-mode voltage. Six simultaneous channels of data are transmitted by direct wire or by one or three simultaneous channels over standard telephone lines to a central recording console. Multiple leads are simultaneously monitored and recorded from a slave oscilloscope onto 35 mm. film premounted on standard computer punch cards (camera cards). The film is automatically developed in 45 seconds. Standard-sized prints of the electrocardiogram are made with standard microfilm printers for return to the patient area. The electrocardiogram may be viewed immediately over closed-circuit television by use of the camera card. The use of 35 mm. film on punch cards allows more efficient and economic handling. Storage and retrieval of electrocardiographic and vectorcardiographic interpretive data are facilitated. Simultaneous output to magnetic tape or on-line computer facilities is possible.