Quantitation of the normal Frank and McFee-Parungao orthogonal electrocardiogram in the adolescent

A detailed linear, circular and spherical quantitation of the Frank and McFee-Parungao orthogonal electrocardiograms of 166 adolescents is presented.

There are significant differences between pubescent males and females: (1) QRS and T magnitudes in the male are greater than in the female. (2) The difference in magnitudes is greater at age 11-15 than at age 16-19, presumably because females reach puberty earlier. (3) The differences in magnitudes are on the X and Z axes but not the Y axis. (4) Males achieve their maximal posterior QRS orientation sooner than females and are more superior as it occurs. (5) The female's T vector is less anterior than the male's. (6) The angular deviation of T from QRS is less in females than males for the horizontal and sagittal planes.

There are significant differences between the two lead systems: (1) The McFee-Parungao's voltages are greater than those of the Frank system. (2) On the X axis, the Frank leftward vector is 62% of the McFee, but the terminal rightward vector is 85% of the McFee. (3) On the Y axis, the Frank inferior vector is 76% of the McFee, but initial superior is 90% and the terminal superior 62% of the McFee. (4) On the X axis, 25% is terminally to the right in the Frank, but only 15% in the McFee. (5) The Frank system is oriented slightly more posterior than the McFee, though the T vectors are not oriented differently.

There is no evidence that the spatial QRS and T orientations are related to each other.

Role of kinetic energy in pulmonary valvar pressure gradients

Peak systolic pulmonary valvar pressure gradients are frequently seen in large intracardiac left-to-right shunt lesions. Conventionally, this has been attributed to "relative" pulmonic stenosis. Theoretical considerations suggest that this gradient is due to differences in expression of the total fluid energy. The side pressure, the downstream pressure, the end pressure, and the flow velocity in the pulmonary artery (PA) and the right ventricle (RV) pressure were measured in 11 dogs in the control state, and after increasing the velocity of the pulmonary arterial flow either by administration of isoproterenol or atropine, or by creating an arteriovenous fistula. The RV pressure and the end PA pressure were not significantly different ( P > 0.05), and were higher ( P < 0.01) than the side and downstream PA pressure in the control state, but increased to higher levels ( P < 0.01) after increasing the velocity of flow in the pulmonary artery. The mean pulmonary valve peak systolic gradient (RV-side PA pressure difference) was 8.8 mm Hg in the control state and increased to 19.1 mm Hg after isoproterenol infusion ( P < 0.01). This change in pulmonary valvar gradient is proportional to the increase in the PA flow velocity.

The side pressure measures only the potential energy, and the end pressure measures both the potential and kinetic energies. In the right ventricle, only the potential energy is recorded where the kinetic energy is practically nonexistent. The difference between the RV (or end PA) pressure and side PA pressure is proportional to velocity of flow in the pulmonary artery and is due to partial transformation of fluid energy into kinetic energy. Thus, our study helps to explain the pressure gradient across the pulmonary valve in large left-to-right shunt lesions. These studies also raise questions as to the validity of interpretations of the gradients produced in the RV outflow tract after isoproterenol or exercise.

Growth retardation in steroid dependent asthma corrected by corticotrophin (ACTH). Case reports with comments

When longterm corticosteroid therapy is found necessary in children during their growth period, their linear growth should be monitored very carefully. If evidence of growth re tardation occurs, then a change to ACTH should be considered.