To allow an exchange of measurements and criteria between different electrocardiographic (ECG) computer programs, an international cooperative project has been initiated aimed at standardization of computer-derived ECG measurements. To this end an ECG reference library of 250 ECGs with selected abnormalities was established and a comprehensive reviewing scheme was devised for the visual determination of the onsets and offsets of P, QRS, and T waves. This task was performed by a group of cardiologists on highly amplified, selected complexes from the library of ECGs. With use of a modified Delphi approach, individual outlying point estimates were eliminated in four successive rounds. In this way final referee estimates were obtained that proved to be highly reproducible and precise. This reference data base was used to study measurement results obtained with nine vectorcardiographic and 10 standard 12-lead ECG analysis programs. The medians of program determinations of P, QRS, and T wave onsets and offsets were close to the final referee estimates. However, an important variability could be demonstrated between measurements from individual programs and mean differences from the referee estimates amounted to 10 msec for QRS for certain programs. In addition, the variances of all programs with respect to the referee point estimates were variable. Some programs proved to be more accurate and stable when the data from high-vs low-noise recordings were analyzed. Average Q wave durations calculated from ECGs for which programs agreed on the presence of a Q or QS wave differed by more than 8 msec in several program-to-program comparisons. Such differences may have important consequences with respect to diagnostic performance. Various factors that might explain these differences have been determined. The present study demonstrates that to allow an exchange of results and diagnostic criteria between different ECG computer programs, definitions, minimum wave requirements, and measurement procedures urgently need to be standardized.Circulation 71, No. 3, 523-534, 1985. DURING the last decade rapid growth has occurred in computer electrocardiographic (ECG) processing.1-3 At present, however, no standards for quantitative ECG analysis exist. There is a lack of agreement on The authors academic affiliations are listed in the Common Standards for Quantitative Electrocardiography (CSE) organizational structure that appears before the references.

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Observations were made on eight normotensive subjects and on 12 patients with essential hypertension to determine whether the intrarenal distribution of blood flow is altered in essential hypertension. Dye-dilution curves were recorded across the renal vascular bed and a set of integral transformations, developed by Gomez, was used to determine distribution of blood flow per unit renal blood volume across the renal vascular bed from dye-dilution curves. Observations also were made on two hypertensives and two normotensives during administration of norepinephrine. The distribution of specific blood flow and the functional renal blood volume in the right kidney of patients with essential hypertension were comparable to those in normal subjects, but the mean specific blood flow was reduced in essential hypertension. Failure to demonstrate altered distribution of specific blood flow in essential hypertension indicated an absence of focal reductions in renal blood flow and that blood flow is reduced uniformly throughout the renal vascular bed in essential hypertension. This reduction in specific renal blood flow is attributed to arteriolar vasoconstriction. ADDITIONAL INDEXING WORDS NephrosclerosisIndicator-dilution technique Norepinephrine

Information and communication technologies (ICT) offer innovative formats for promoting healthy lifestyles and reinforcing public health initiatives. They can be applied to large population segments without losing the functionality of being tailored to individual fluctuating needs. Advantages of ICT include real-time provision and adaptation of nutrition and health recommendations based on an individual's particular situation, the potential to combine assessment procedures with healthy lifestyle support and the ability to unify psychosocial and cultural dimensions to enhance adherence. Two pilot programs are presented that show the potential for applying ICT to the promotion of healthy eating and physical activity habits.