This paper presents a new electrocardiographic lead system consisting of 9 QRS waveforms and labelled 'optimal', 'total' or 'maximal' because of the following reasons: Nine QRS waveforms were found capable of resynthesizing any surface electrocardiogram (QRS) recorded on the thoracic surface. The 9 recording sites are identically located for each individual whether normal or not. These 9 leads, accounting for the total available surface waveform information, increased the diagnostic performance (in bi group differentiations) of the Frank leads by an average of 14%. Since bi group classifications are, from a clinical point of view, of limited value for studies in which more than two possibilities are to be faced simultaneously, multigroup classification is presented here and misclassification rates of the 9 lead system and the Frank leads are compared.
A 32-year follow-up of the first coarctations of the aorta ever operated upon in the world has shown a systolic blood pressure below 155 mmHg in 12 of 18 patients and a diastolic blood pressure below 95 mm Hg in 15 of 18 patients. No gradient over the anastomosis was noted in 13 of 18 patients when measured by a cuff and in 5 of 12 patients when measured by catheterization. If the diameter of the anastomosis was 75% of that of that of the aortic arch, only a very small or no resting gradient was found. If there was no gradient at rest, there was usually only an insignificant or no gradient during exercise. A small gradient at rest was always higher during exercise, depending on the degree of work load, length of narrowed segment and aneurysm at the suture line. There was an incidence of 44% aortic valvular disease and of 20% degenerative changes in caput femoris. The anastomosis had grown with the patient.
