To objectively reappraise the role of the chest radiograph (CXR) in the clinical assessment of emphysema, we compared a standardized reading of CXR with both a visual scoring and a quantitative analysis of high resolution computed tomography (HRCT) of the chest in 46 consecutive patients with chronic obstructive pulmonary disease (COPD) and fixed expiratory airflow limitation. CXR were scored for signs of overinflation and pulmonary vascular deficiency by three independent observers. HRCT scans were independently scored for extent of emphysema and for both severity and extent of emphysema. In 28 of 46 patients, inspiratory and expiratory HRCT scans were analyzed quantitatively by measuring the mean CT number in Hounsfield Units (HU) and the percentage of lung area with CT numbers < -900 HU. Quantitative CT data were compared with reference values obtained in seven normal nonsmokers. The CXR score of emphysema showed a highly significant interobserver reproducibility and correlated linearly (p < 0.001) with HRCT visual scores and quantitative data from both inspiratory and expiratory CT scan. CXR score correlated with functional indices of airflow obstruction, overinflation, and impaired lung diffusing capacity in a way comparable to that obtained by using qualitative and quantitative CT data. Patients with no signs of emphysema on CXR had mean expiratory CT numbers within normal range and a fraction of lung area with CT numbers < -900 HU on expiratory scan not exceeding 15% of total cross-sectional area. The latter value was consistently greater than 15% in patients with CXR score > 0.(ABSTRACT TRUNCATED AT 250 WORDS)

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In 7 conscious dogs, left ventricular diastolic volume (V) was estimated by taking biplane cineradiographs with the left ventricular cavity previously outlined by permanent radiopaque markers. Left ventricular pressure (P) was measured with an implanted miniature transducer. There were two rapid filling periods during early and late diastole; little filling occurred during the middle third of diastole (diastasis). The diastolic pressure-volume relationship was approximately exponential and was fitted by the equation P = -a + be cY , where a, b, and c are positive constants; the relationship appeared to be determined principally by the elastic properties. The effects of infusions of saline, isoproterenol, calcium gluconate, and methoxamine suggested that viscous and inertial properties are also important determinants of diastolic left ventricular mechanics. No significant series viscosity was observed. Plastic properties were not detected. The elastic properties were not affected by agents having a positive inotropic effect. End-diastolic pressure often differed from that predicted by the exponential equation above, suggesting that it is not a reliable index of enddiastolic volume and left ventricular compliance. ADDITIONAL KEY WORDStantalum markers biplane cineradiography end-diastolic pressure left ventricular compliance isoproterenol elastic components myocardial plasticity series viscous element inertial properties left ventricular distensibility calcium methoxamine• The present study was undertaken to answer the following questions in the conscious dogs: (a) how does the volume of the left ventricle change during diastole; (b) what is the relationship between left ventric-

Pulmonary function abnormalities after exercise are suggestive of pulmonary edema; however, radiographic evidence is lacking. Well-trained cyclists were studied to determine whether there is radiographic evidence of pulmonary edema after endurance exercise (cycling distance 5.3-131.5 km) at altitude. Chest radiographs obtained before exercise were coded for later interpretation. Films obtained after exercise were coded with a different number. A total of 74 sets of posteroanterior and lateral films were analyzed by three radiologists for signs of pulmonary edema. Radiographic changes were graded on a three-point scale. An edema score was calculated by summing the score for each individual radiographic finding for each radiologist and an overall edema score representing the mean scores from all three radiologists. The overall edema score increased from 0.8 +/- 1.2 before exercise to 1.8 +/- 1.6 after exercise (P < 0.01). These results suggest that, after prolonged high-intensity exercise at moderate altitude, there is radiographic evidence of early pulmonary edema in some cyclists.

An increase in heart rate produced in 12 conscious dogs by right atrial pacing resulted in a fall of end-diastolic volume, stroke volume, stroke work and end-diastolic pressure. Stroke power and the maximum rate of increase of left ventricular pressure (LV dP/dt max) were affected only slightly. Sudden large changes of rate produced transient changes in LV dP/dt max typical of the positive and negative inotropic effects of activation, but steady-state LV dP/dt max was not affected; these effects persisted after autonomic blockade with propranolol and atropine. Postural changes produced no change in LV dP/dt max even after autonomic blockade. We conclude that in this preparation, the interval-strength relationship has a plateau at the physiologic range of heart rate, i.e., myocardial contractility is unaffected by change in heart rate over the range 90 to 190 beats/min. ADDITIONAL KEY WORDS end-diastolic volumeright atrial pacing inotropic effects of activation posture autonomic blockade myocardial contractility frequency of contraction LV dP/dt max interval-strength relation• Interpretation of the results of heart studies are sometimes complicated by changes in heart rate. We previously investigated the effect of heart rate per se on left ventricular contraction, found that left ventricular stroke volume fell linearly with increase in heart rate, and speculated on the possibility that this resulted from a concomitant fall in enddiastolic volume (1). One of the purposes of the present study was to investigate this question directly.In other studies (2) we found that the This work was supported in part by U. S. Public Health Service Grants HE-06285, HE-06851, and HE 5251 from the National Heart Institute. Dr. Noble was a Senior Fellow of the San Francisco Bay Area Heart Research Committee. Dr. Milne was a Fellow of the Ontario Cancer Foundation.Received for publication lune 24, 1968. Accepted for publication December 24, 1968. maximum acceleration of blood from the left ventricle is greatly affected by procedures that change myocardial contractility. The finding that maximum acceleration was little affected by changes in heart rate (1) therefore suggested that myocardial contractility was little affected by changes of heart rate over the physiologic range in conscious dogs. The definition of myocardial contractility is difficult and controversial (3) but it is doubtful whether any benefit is to be derived by using a different term. We have assumed that a change in left ventricular contraction, which is not caused by a change in initial fiber length or load, must result from a change of contractility, but recognize that we can only measure limited aspects of contractility. Our second objective in the present study was to investigate the effect of heart rate on myocardial contractility in greater depth. Methods Twelve mongrel dogs with implanted flow and

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The purpose of this study was to assess lung function in runners with marathon‐induced lung edema. Thirty‐six (24 males) healthy subjects, 34 (SD 9) years old, body mass index 23.7 (2.6) kg/m2 had posterior/anterior (PA) radiographs taken 1 day before and 21 (6) minutes post marathon finish. Pulmonary function was performed 1–3 weeks before and 73 (27) minutes post finish. The PA radiographs were viewed together, as a set, and evaluated by two experienced readers separately who were blinded as to time the images were obtained. Radiographs were scored for edema based on four different radiological characteristics such that the summed scores for any runner could range from 0 (no edema) to a maximum of 8 (severe interstitial edema). Overall, the mean edema score increased significantly from 0.2 to 1.0 units (P <0.01), and from 0.0 to 2.9 units post exercise in the six subjects that were edema positive (P = 0.03). Despite a 2% decrease in forced vital capacity (FVC, P =0.024) and a 12% decrease in alveolar‐membrane diffusing capacity for carbon monoxide (DmCO, P =0.01), there was no relation between the change in the edema score and the change in DmCO or FVC. In conclusion, (1) mild pulmonary edema occurs in at least 17% of subjects and that changes in pulmonary function cannot predict the occurrence or severity of edema, (2) lung edema is of minimal physiological significance as marathon performance is unaffected, exercise‐induced arterial hypoxemia is unlikely, and postexercise pulmonary function changes are mild.