Showing papers by "Ronald M. Lauer published in 1970"

The First Derivative Thoracic Impedance Cardiogram

Abstract: When an alternating current of high frequency is applied to the thorax, the first derivative of the impedance to this current is affected by the cardiac cycle resulting in a characteristic wave form. Phonocardiograms, electrocardiograms, and first derivative thoracic impedance cardiograms were recorded simultaneously in 91 subjects. The first derivative thoracic impedance cardiograms were found to have sharply demarcated points which occur synchronously with the first heart sound, aortic second sound, pulmonic second sound, mitral opening snap, third heart sound, and fourth heart sound. The first derivative thoracic impedance cardiogram may thus be used not only as a reference tracing to help identify heart sounds on the phonocardiogram, but also for directly timing the intervals within the cardiac cycle.

Intra-abdominal hemorrhage complicating a balloon atrial septostomy for transposition of the great arteries.

Abstract: In 1966, Rashkind and Miller1 described a non-surgical technique for palliation of transposition of the great arteries by using a balloon-tipped intracardiac catheter to create an atrial septal defect. This method has been frequently employed, as reported by several [see pdf for the Figure] authors2,3. The purpose of this report is to describe a patient with intra-abdominal hemorrhage as a complication of this procedure. Case Report A 2-week-old male infant was seen at The University of Iowa Hospitals with the chief complaint of intermittent cyanosis since birth. Physical examination, electrocardiogram, and chest x-ray were compatible with the clinical diagnosis of transposition of the great arteries.