Jose L. Gimenez

Venoarterial shunting from inferior vena cava to left atrium in atrial septal defects with normal right heart pressures: Report of two cases

Abstract Two unusual cases of atrial septal defect are presented with right to left shunting occurring from functional drainage of the inferior vena cava into the left atrium. The first had been unrecognized in a teenage boy who previously had undergone successful closed pulmonary valvotomy for congenital pulmonary valvular stenosis. The second occurred following a right pneumonectomy for bronchogenic carcinoma in a man with a previously undetected atrial septal defect. The respiratory embarrassment developing postoperatively was related to dislocation of the heart resulting in an anatomic shift of the atrial septum so that the inferior cava emptied directly into the septum secundum defect. Both patients had normal right heart pressures, and in each the diagnosis was established by selective dye-dilution curves and confirmed by selective cineangiography. Blood gas studies were instrumental in the second case in pointing toward a right to left shunt subsequently confirmed by dye-dilution studies. The importance of blood pH, pCO 2 , and pO 2 studies and selective indicator-dilution studies in the evaluation of patients with unexplained cyanosis or respiratory distress is emphasized.

Clinical application of ultrasound in the analysis of prosthetic ball valve function

Abstract The ultrasonic pulse reflection technic provides a means of recording time-displacement curves of prosthetic ball or cage motion which closely correlate with similar time-displacement curves plotted from cinefluorographic film. Precise correlation with events recorded by phonocardiogram, electrocardiogram, apex cardiogram and pressure curves is easily accomplished. Prosthetic aortic and mitral balls maintain normal timing characteristics with the apex cardiogram when compared with normal aortic and mitral valves, but the contour of mitral prosthetic ball motion resembles that of mitral stenosis. This is thought to be the result of the flow characteristics through a prosthetic valve rather than a representation of true stenosis. Opening and closing of these valves is clearly related to appropriate crossover pressure changes. The origin of systolic clicks from aortic prostheses and diastolic clicks from mitral prostheses appears related to bounces or vibratory motion at the apex of the respective cages. Cage motion reflects motion of the ring to which the valve is anchored. Thus, considerable motion of the mitral cage reflecting motion of the atrioventricular ring is normal, but only slight motion of the aortic ring is seen. Precise timing of the balls of multiple valve replacement with relation to each other may be obtained by modification of existing instrumentation to permit the recording of more than one signal. The velocity of the opening and the closing ball within a cage may be obtained by direct measurement of slope or, perhaps more accurately, by electronic recording of the first derivative of displacement in relation to time. Mitral ball closing velocity is nearly double opening velocity. Aortic ball closing velocity slightly exceeds opening velocity by direct measurement. Observations on ball velocity may provide information on valvular function if studied over a long period of time.

Cineradiographic frame rate selection for left ventricular volumetry.

The left ventricular volume curve was plotted from biplane cineangiograms at 270 frames per second, using Simpsons rule to measure the volume. Fourier transformation was applied to obtain the frequency spectrum of the curve. Volume curves at slower rates were produced. Curves with less than 5% error can be generated at 15 frames per second because of the low frequency content. This rate of filming was adequate to measure left ventricular volume by biplane cineradiography.

Addition of polymer to radiopaque contrast material to decrease catheter flow resistance.

RECENT SHIP-MODEL studies have shown that long-chain, high-molecular-weight polymers reduce fluid-friction drag on ship hulls (2). A similar effect was demonstrated in pipeline flows and was quickly adapted by various industries interested in reducing the cost of pumping fluids through pipelines. Recent experiments have explored the biological applicability of this phenomenon (3, 5). This report describes the use of long-chain, high-molecular-weight polymers to reduce frictional drag in high-speed injection catheters. Previous work in this laboratory (1) has shown that catheters used clinically in high-speed injections generally operate in a turbulent flow condition. Reynolds numbers in the range of 6,000–15,000 are found in catheters under these conditions. The application of classical engineering hydrodynamics is useful in the description of pressure-flow characteristics of injection catheters (1). The addition of high-molecular-weight polymers reduces frictional drag only in turbulent flow conditions. ...