Ira H. Gessner

“Harvey,” the cardiology patient simulator: Pilot studies on teaching effectiveness

Abstract The final prototype of “Harvey,” a cardiology patient simulator, was completed in 1976. A review and critique of the simulators nonauscultatory and auscultatory physical findings by cardiologists indicated that the simulator was capable of faithfully reproducing the blood pressure, jugular venous pulsations, carotid and peripheral arterial pulsations, precordial impulses and auscultatory events of almost all cardiac diseases. Pilot studies using the simulator in a formal senior medical student elective program in cardiology showed an average gain in bedside examination skills of 32 percent ( p To assess the acceptability of the device, 770 undergraduate and graduate physicians, family practitioners, internists and cardiologists were exposed to the cardiology patient simulator. Their reaction was positive, 93 percent rating it excellent and 100 percent wishing to be taught with the device again in the future. Prolonged periods of use demonstrated the technical reliability of the simulator. Formal multicenter studies are now underway that will assess its effectiveness as a teaching and testing device. The long range goals of these efforts remain: (1) to produce better trained physicians in less time and at less cost; and (2) to provide an objective method to measure the clinical competency and skills of students and physicians in patient-oriented examinations, such as those for Board certification and recertification.

Spectrum of Congenital Cardiac Anomalies Produced in Chick Embryos by Mechanical Interference with Cardiogenesis

Stage 19 to 20 white leghorn chick embryos were subjected to an operative manipulation in which a wire device was passed under the outflow tract of the cardiac tube, and allowed to remain in place from 24 to 60 hours. The embryos were then permitted to develop until hatching. Twenty-eight embryos, including eight sham operated controls, all of whom were normal, survived to at least the 18th embryonic day, and are included in this report. A spectrum of cardiac anomalies was produced as follows: group 1, widening of the left ventricular outflow tract unassociated with other defects; group 2, widening of the left ventricular outflow tract with a subaortic ventricular septal defect, 0.8 mm or less in its greatest dimension; group 3, a large ventricular septal defect, 1.5 mm or more in its greatest dimension, with varying degrees of abnormal position of the aorta, including “overriding” of the aorta, but with maintenance of continuity between the aortic and mitral valve annuli; group 4, the double outlet syndrome, in which both great vessels arise from the anatomic right ventricle with complete muscular separation between the aortic and mitral valves. In the time period studied, the double outlet syndrome represents the extreme of the continuum. However, it is possible that other forms of this spectrum exist, some perhaps incompatible with embryonic life, and that these may be produced by changing the experimental technique.

Pathogenetic mechanisms in congenital cardiovascular malformations

C ONGENITAL ANOMALIES have aroused man’s curiosity, superstition, fear, and awe for many centuries. Explanations concerning their etiology and pathogenesis based upon supernatural forces, fatalism, mysticism, philosophy, and scholarly, if not always well founded, scientific reasoning have been offered for almost as long a time. Cardiac anomalies have enjoyed more than their share of interest, either because they are common and usually have profound influence on the life of the individual, or because the heart is an organ which has always had a certain special significance for man, possibly because it seems to have such an obvious, active life of its own within the body and reacts so rapidly and obviously to changes in man’s emotional status. To date, no one has had the opportunity to actually observe the pathogenesis of cardiovascular malformations by systematic study of embryologic material. While it has been possible for many years to induce cardiac (and other) anomalies in experimental animals, the effect of various teratogens appears to be rather nonspecific, and, therefore, the malformations produced by any one agent are not consistently all of the same type. Stockard’ concluded from his classical work with Fundulus that different disturbances applied at the same phase of development would tend to produce the same defects, whereas the same disturbing factor applied at different phases of development produces different defects. While this may be somewhat of an oversimplification, there seems to be little doubt that in many, if not most cases, the nature of the injurious agent is not as important a determining factor as the precise time in early development at which it is allowed to exert its influence. Such exact timing in administering an experimental insult is virtually impossible, certainly so in mammals. Thus, it has not been possible as yet to induce transposition complexes, tetralogy of Fallot, or any other specific anomaly reproducibly, and in a high enough percentage of offspring to render embryologic studies practicable and reliable. For this reason, experimental work aimed at producing cardiac anomalies has little or no value for the study of the pathogenesis of such anomalies. Recently, Gessne? has been able to create cardiac anomalies of a fairly uniform type (double outlet right ventricle and double inlet left ventricle) in chick embryos by mechanical means. Undoubtedly, the reason such uniform results

The Circulatory and Respiratory Adaptation to Early and Late Cord Clamping in Newborn Infants

Time of first breath and frist cry, systolic blood pressure, pulse rate and respiratory rate of 32 newborn infants whose umbilical cords were clamped early and 30 whose cords were tied late after birth were studied. The early clamped infants breathed significantly sooner after birth than the late clamped infants, probably a result of anoxia due to severance of placental blood supply by immediate cord clamping. The indirectly measured sys‐ tolic blood pressure was significantly higher in the late clamped group of infants during the first 24 hours of life perhaps due to the difference in blood volumes between the two groups. This is further supported by a positive correlation found between systolic blood pressure and venous hematocrit during the first 4 hours of life. Pulse rate in the two groups of infants studied revealed no significant difference. The respiratory rate in the early clamped group of infants was significantly slower during the 1st to the 3rd hour of life when compared with the late clamped infants. No satisfactory explanation could be offered for this observation.

The morphologic development of the sinoatrial node in the mouse

Abstract A plastic embedding technique was employed on mouse embryos after fixation with a gluteraldehyde-paraformaldehyde mixture and preparation of large, 1 to 2 μ sections cut on a rotary microtome with steel knives. It was then possible to trace the sinoatrial node back to mouse embryos of 4 sol1 2 mm crown-rump length ( 10 1 2 days gestational age, corresponding developmentally to 6 mm human embryos). In the mouse, the sinoatrial node lies anteromedially just above the cavoatrial junction. The nodal artery, which is located more or less centrally, is a branch of the internal mammary artery, not of the coronary arterial system. Even in the youngest embryos examined thus far, the node is strictly unilateral in structure.

Experimental production of cardiac defects: The spectrum of dextroposition of the aorta

An experimental technique, involving temporary mechanical displacement of the truncoconus of chick embryo hearts (Hamburger and Hamilton stages 19 to 20), results in a spectrum of congenital heart defects characterized by varying degrees of dextroposition of the aorta. These defects include isolated ventricular septal defects, ventricular septal defect with overriding aorta, double outlet right ventricle, and double outlet right ventricle plus double inlet left ventricle. The pathogenesis of these anomalies is considered to be rightward and anterior displacement of the conal septum, preventing its normal alignment with the ventricular septum. Observations of a large number of specimens have emphasized the overlap of one diagnostic category into another. Each of these defects occurs spontaneously in the chick and in man. Similarities and differences in the pathology and the suspected pathogenesis are discussed.

Serum creatine phosphokinase MB fraction in newborns with transient tricuspid insufficiency.

RECENTLY, we reported 14 term newborn infants affected by severe perinatal stress who subsequently manifested cyanosis, congestive heart failure and transient murmurs of tricuspid insufficiency.1 T...

Pulmonary arterial pressures of newborn infants born with early and late clamping of the cord.

Hemodynamic studies were conducted on 32 normal, full‐term newborn infants, age 29 minutes to 11 hours, to determine the effect of placental transfusion upon the pulmonary circulatory adjustments after birth. In 10 infants, clamping of the cord was accomplished within 2 to 10 seconds after the delivery (early clamping), and in the other 22 infants it was done after cessation of the umbilical arterial pulsations (late clamping).

Ostium secundum atrial septal defect associated with balloon mitral valve in children

Abstract Eight children with an ostium secundum atrial septal defect and balloon mitral valve are described. Leftward-superior QRS forces, abnormal T waves and suggestive apical auscultatory findings (midsystolic click or a late systolic murmur of mitral insufficiency) were frequently observed and led to the erroneous diagnosis of ostium primum atrial septal defect in six cases. Lack of any or all of these manifestations did not preclude the presence of a balloon mitral valve. The prognostic importance of this valvular lesion indicates the need to perform left ventriculography in all patients with an atrial septal defect.

A New Method Utilizing Indicator-Dilution Technics for Estimation of Left-to-Right Shunts in Infants

The short circulatory pathways of infants cause rapid systemic and pulmonary circulation times. So rapid are they that the usual methods for calculating left-to-right shunts frequently yield a considerable overestimation. A new formula was described for use with injections into the left heart and arterial sampling. This formula applied to 11 infants and 7 older patients showed a significantly better correlation with oximetric calculations than did the right heart injections. This method also will reveal the presence of a left-to-right shunt that is of insufficient magnitude to distort dye curves obtained following right heart injections.