Carleton B. Chapman

Use of Biplane Cinefluorography for Measurement of Ventricular Volume

A biplane cinefluorographic technic for measuring ventricular volume is described and its accuracy and limitations are assessed. Although rather complicated and time-consuming at present, the method permits construction of volume curves and estimation of stroke volume of the left ventricle for several successive contractions in the intact animal or man. This method may prove most useful for physiologic research and ultimately for diagnostic purposes.

A Longitudinal Study of Adaptive Changes in Oxygen Transport and Body Composition

The effects of a 20-day period of bed rest followed by a 55-day period of physical training were studied in five male subjects, aged 19 to 21. Three of the subjects had previously been sedentary, and two of them had been physically active. The studies after bed rest and after physical training were both compared with the initial control studies. Effects of Bed Rest All five subjects responded quite similarly to the bed rest period. The total body weight remained constant; however, lean body mass, total body water, intracellular fluid volume, red cell mass, and plasma volume tended to decrease. Electron microscopic studies of quadriceps muscle biopsies showed no significant changes. There was no effect on total lung capacity, forced vital capacity, one-second expiratory volume, alveolar-arterial oxygen tension difference, or membrane diffusing capacity for carbon monoxide. Total diffusing capacity and pulmonary capillary blood volume were slightly lower after bed rest. These changes were related to changes in pulmonary blood flow. Resting total heart volume decreased from 860 to 770 ml. The maximal oxygen uptake fell from 3.3 in the control study to 2.4 L/min after bed rest. Cardiac output, stroke volume, and arterial pressure at rest in supine and sitting positions did not change significantly. The cardiac output during supine exercise at 600 kpm/min decreased from 14.4 to 12.4 L/min, and stroke volume fell from 116 to 88 ml. Heart rate increased from 129 to 154 beats/min. There was no change in arterial pressure. Cardiac output during upright exercise at submaximal loads decreased approximately 15% and stroke volume 30%. Calculated heart rate at an oxygen uptake of 2 L/min increased from 145 to 180 beats/min. Mean arterial pressures were 10 to 20 mm Hg lower, but there was no change in total peripheral resistance. The A-V 02 difference was higher for any given level of oxygen uptake. Cardiac output during maximal work fell from 20.0 to 14.8 L/min and stroke volume from 104 to 74 ml. Total peripheral resistance and A-V 02 difference did not change. The Frank lead electrocardiogram showed reduced T-wave amplitude at rest and during submaximal exercise in both supine and upright position but no change during maximal work. The fall in maximal oxygen uptake was due to a reduction of stroke volume and cardiac output. The decrease cannot exclusively be attributed to an impairment of venous return during upright exercise. Stroke volume and cardiac output were reduced also during supine exercise. A direct effect on myocardial function, therefore, cannot be excluded. Effects of Physical Training In all five subjects physical training had no effect on lung volumes, timed vitalometry, and membrane diffusing capacity as compared with control values obtained before bed rest. Pulmonary capillary blood volume and total diffusing capacity were increased proportional to the increase in blood flow. Alveolar-arterial oxygen tension differences during exercise were smaller after training, suggesting an improved distribution of pulmonary blood flow with respect to ventilation. Red cell mass increased in the previously sedentary subjects from 1.93 to 2.05 L, and the two active subjects showed no change. Maximal oxygen uptake increased from a control value of 2.52 obtained before bed rest to 3.41 L/min after physical training in the three previously sedentary (+33%) and from 4.48 to 4.65 L/min in the two previously active subjects (+4%). Cardiac output and oxygen uptake during submaximal work did not change, but the heart rate was lower and the stroke volume higher for any given oxygen uptake after training in the sedentary group. In the sedentary subjects cardiac output during maximal work increased from 17.2 L/min in the control study before bed rest to 20.0 L/min after training (+16.5%). Arterio-venous oxygen difference increased from 14.6 to 17.0 ml/100 ml (+16.5%). Maximal heart rate remained constant, and stroke volume increased from 90 to 105 (+17%). Resting total heart volumes were 740 ml in the control study before bed rest and 812 ml after training. In the previously active subjects changes in heart volume, maximal cardiac output, stroke volume, and arteriovenous oxygen difference were less marked. Previous studies have shown increases of only 10 to 15% in the maximal oxygen uptake of young sedentary male subjects after training. The greater increase of 33% in maximal oxygen uptake in the present study was due equally to an increase in stroke volume and arteriovenous oxygen difference. These more marked changes may be attributed to a low initial level of maximal oxygen uptake and to an extremely strenuous and closely supervised training program.

Measurement of right ventricular volume by cineangiofluorography

Abstract A method for measuring the volume of both ventricles in dogs over several cardiac cycles is available; it demonstrates significant differences, from moment to moment, in ejection patterns of the two ventricles but confirms the fact that stroke volumes are usually identical. The volume of the interventricular septum was found to be relatively large at rest; it amounts to about 50 per cent of the stroke volume under the conditions of the experiments.

Experiences with a cinefluorographic method for measuring ventricular volume

Abstract The development of cineroentgenographic methods for following changes in left ventricular, and other chamber volumes has been reviewed. Since injections of contrast media and repeated exposure to radiation are to some extent hazardous, and since cineroentgenographic methods can never provide data for more than a small number of consecutive cycles, they cannot be considered ideal. The ideal method would require no injection, would subject the subject to no hazard, and should be applicable for long periods of time, regardless of the position or activity of the subject. To date, no such system has been devised. For the foreseeable future, carefully designed multiplane cineroentgenographic methods, combined with scanning devices for digitizing data obtained from film images, offer the greatest promise despite inherent defects.

A scanner-computer for determining the volumes of cardiac chambers from cinefluorographic films.

In the use of biplane cineroentgenographic and serial x-ray techniques for measurement of the volume of various cardiac chambers, mechanical and electronic adjuncts to facilitate tracing chamber boundaries and to carry out the necessary calculations were devised. The method for whicli the described instruments were developed requires the tracing of 2 simultaneously filmed images (35-mm film) recorded at a rate of 30 per sec. The tracing equipment is also described. A scanner is used to measure the diameters of the traced figures and to transmit the result to a photomultiplier tube which then transmits it to a computer. Counting is accomplished by a pulse generator situated between the photomultiplier tube and the computer. A multiplier accepts impulses from the photomultiplier tube in the scanner unit and multiplies the 2 image diameters. The result is transmitted to an accumulator, which sums and stores the results. After the final scan, a stop mark on the slotted paper signals the logic compartment, which, in turn, activates the printer. The scanner-computer was applied to calculation of left ventricular volumes in dogs and in man. (TCO)

The maximal oxygen intake test in patients with predominant mitral stenosis. A preoperative and postoperative study.

I N FUNCTIONALLY significant mitral stenosis the value of surgical reduction of the block to left atrial outflow is not firmly established. Methods for objective measurement of the degree of functional impairment before and after operation have been slow in development. The critical use of symptoms, physical signs, x-ray films, and electrocardiograms is undoubtedly the first resort for this purpose, and in many cases it is sufficient. In some instances, however, these technics leave important questions unanswered; symptoms do not always fit signs and, most important, subjective improvement after operation is almost the rule even when the usual methods of clinical examination disclose little or no innprovement. Attempts to use quantitative hemodynamic and respiratory methods for evaluation have often been disappointing in that they frequently throw very little light on subjective improvement induced by operation.1 It may indeed be held that, in the selection of patients for surgery, the superiority of such sophisticated methods over the astute use of ordinary clinical tools has not been demonstrated. It was inherent in the work by Hickam and Cargill2 over a decade ago, and in subsequent studies by Gorlin and co-workers,3 that resting hemodynamie and respiratory studies might be of limited value in the functional evaluation of patients with mitral stenosis unless combined with exercise studies. More re-

The cinefluorographic approach to the diagnosis of mitral regurgitation.

Summary Cineangiofluorography, even in its present imperfect state, provides very useful information on the anatomy of mitral regurgitation and fair estimates of its magnitude. Differentiation between anterior and posterior commissural involvement is possible by cineangiofluorographic means even though other filming technics fail to make the distinction. It is suggested that the morphology of left atrial enlargement may not be the same for mitral regurgitation that develops over a long period of time, as for that which develops acutely. Finally, cineangiofluorography, by making possible the calculation of chamber volumes, may ultimately furnish the most precise and reliable method of accurate measurement of mitral regurgitation in absolute units.

Left Ventricular Residual Volume in the Intact and Denervated Dog Heart

Left ventricular volumes were measured at rest and during electrically stimulated muscular exercise in 28 anesthetized dogs. Volumes were calculated from images obtained during biplane cineangiofluorography. Under control resting conditions from 30 to 55% of the diastolic volume of the left ventricle remained after ejection. This residual volume of blood became an immediate source of the increased ventricular output during the beginning of exercise. Following vagectomy, sympathectomy, and total cardiac denervation, the ability to increase cardiac output during exercise persisted, but was accomplished by increased ventricular filling rather than by diminution of the residual volume.

The interpretation and diagnostic value of oximetrically-recorded T-1824 dye curves in congenital heart disease☆

Abstract Oximetrically recorded T-1824 dye curves offer a relatively reliable means of identifying the site and type of intracardiac and aortic-pulmonary shunts. The most valid indication of the presence of venoarterial admixture is a shortened appearance time (AT). Curves due to left-to-right shunts can be identified by the presence of a normal appearance time and a prolonged descending slope to which disappearance time (DT) is a good index. The use of ratios between certain time intervals obtained from the curves is of questionable value for the identification of the type of shunt present. Double-peaked dye curves usually, but not always, indicate venoarterial admixture but are not as frequently encountered in patients with such shunts as are shortened appearance times. Comparison of oximetric dye curves and those obtained by serial arterial sampling in normal subjects discloses that the former are quantitatively reliable both as to time intervals and as to the area enclosed, provided 10 mg. or more of dye is injected.

ROTATIONAL CINEFLUOROGRAPHY OF THE HEART AND LUNGS.

Abstract A technique of rotational cinefluorography is described in which the patient is rotated through 360 degrees during filming. An electrically operated rotating chair is employed, which automatically alters the x-ray settings to compensate for changing diameters of the chest. The clinical usefulness of the method in localizing pulmonary lesions and in providing permanent fluoroscopic records is already established to a degree. Technical improvements in roentgenographic apparatus are required before the method can be expected to become routine.