Citations

Indicator-dilution curves were recorded by oximeters at the ears and the right radial artery following the injection of Evans blue (T 1824) into the superior vena cava and pulmonary arteries of 37 subjects who had no evidence of cardiovascular disease. The variability and ranges of various time and concentration components of these dilution curves are presented. These values can be used as standards of reference in the interpretation of abnormal dilution curves. Some of the factors responsible for the variability of these values in healthy subjects are assessed and discussed.

Changes in pulmonary vascular (arteriolar) resistance were estimated in 58 patients with mitral stenosis following mitral valvotomy and during exercise. Evidence is presented that changes in "resistance" reflect active changes in the caliber of the vessels due to alteration in their smooth muscle tone, valvotomy being followed by a decrease in tone and exercise by an increase.

Because of reports that derivatives of Rauwolfia serpentina may cause severe mental depression when used in the treatment of hypertension, the depressive reactions and possible contributing factors were studied in a group of 387 hypertensive patients. Some of the patients received no specific antihypertensive medication; some were treated with Rauwolfia derivatives alone and some with Rauwolfia and other antihypertensive drugs. Of the patients receiving Rauwolfia, alone or with other drugs, 26 per cent experienced depressive reactions whereas only 5 per cent of the others had them.

Analysis of accumulated experience with the repair of atrial septal defect in 119 adults has revealed several factors determinable preoperatively that appear to have a strong influence on the operative risk. These factors are related to the presence of pulmonary vascular disease or heart failure and contribute importantly to the selection of patients for operation.

The relative importance of organic changes and vasoconstrictive influences in the production of increased pulmonary vascular resistance in congenital heart disease is problematic. With use of a grading system previously described, a study was made of the relation between each of the grades of hypertensive pulmonary vascular disease associated with ventricular or atrial septal defects and the change of pulmonary artery blood pressure immediately following closure of the abnormal communications. The immediate reversibility of the pulmonary hypertension varies inversely with the severity of the structural changes.

With use of a previously described system of grading, a study was made of the relation between each of the grades of hypertensive pulmonary vascular disease and the hemodynamic findings in the lesser circulation in 15 cases of atrial septal defect, 19 cases of ventricular septal defect, and 6 cases of patent ductus arteriosus.

This series of papers constituted the second Symposium on Cardiovascular Sound conducted in association with the Scientific Sessions of the American Heart Association. The symposium took place on Friday, October 25, 1957, at the Hotel Sherman in Chicago. The chairman of the morning sessions was Dr. Hans H. Hecht of Salt Lake City; Dr. J. Willis Hurst of Atlanta was chairman for the afternoon sessions. The first symposium was published in Circulation 16 : 270, and 414, 1957. This publication was made possible by a grant-in-aid front the National Heart Institute, U.S. Public Health Service, and by contributions from Mr. Arthur L. Humphries, The Rena and Walter Burke Foundation, Lakeside Laboratories, Burroughs-Welcome Company, and the Wyeth Laboratories.

Among 24 cases of small subendocardial infarctions included in this report are 10 cases of anteroseptal distribution in which the electrocardiogram was characterized by the presence of deeply inverted T waves in some or all of the precordial leads. Two other types of change encountered among the remaining 14 cases are described. Electrocardiographic changes in this group of 24 cases are compared with changes encountered in 5 cases of large and near circumferential acute subendocardial infarction described in part I of this study.