Ventricular Gradientの臨床的意義
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概要
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From the theoretical point of view, the concept of the ventricular gradient (VG) is thought to be interesting in the interpretation of the clinical electrocardiogram, but there has been few studies on the relationships between the ventricular gradient and the histologic findings of the ventricular myocardium.The author determined the frontal plane VG from the Einthoven's triangle with Leads 1 and 2 and the horizontal plane VG with Leads V_1 and V_6 in routine electrocardiograms of clinical and autopsied cases.Normal limits of the angle of the VG in fifty healthy young adults were determined. On the basis of these values, there were few abnormalities of the angle of VG in cases of complete right bundle branch block, transitional form to left ventricular strain pattern and so-called myocardial damage, but many abnormal cases were found in right or left ventricular hypertrophy and strain patterns. There were more abnormalities in frontal than in horizontal plane. In cases of right bundle branch block there was no abnormality in the cases which showed no clinical findings of organic heart disease. In right ventricular hypertrophy and strain patterns the author found more abnormalities of the angle of VG in the cases with severe congestive heart failure than without it, but there was no constant relationship between the grade of congestive heart failure and the magnitude of the VG. Furthermore there was no clear difference between the incidence of abnormal VG in congenital malformations of the heart and that in acquired mitral valvular diseases.The magnitude of the VG in both planes showed a tendency similar to the angle of VG, when the lower limit of its magnitude is regarded as 30 microvolt seconds.The manifest magnitude and angle of the VG in both planes obtained from 47 older patients (mean age, 68.5 years) were compared with the autopsied findings. In forty of these patients the magnitude and angle of the VG were compared with the histologic findings of the myocardium.Although no abnormality of the angle of the VG was seen in the autopsied cases with normal electrocardiogram, ther were many abnormalities in the directions of the VG in the cases which showed myocardial infarction or left ventricular hypertrophy and strain patterns.In 74% of the cases which showed abnormalities in the angle of the VG, moderate to severe myocardial fibrosis was seen, irrespective of the patterns of electrocardiogram. But, on the contrary, there was none or slight to mild fibrosis in 85% of the cases with normal VG and no cases of moderate or severe myocardial fibrosis were observed.The relationship between myocardial fibrosis and the magnitude of the VG was the same as that in the angle of VG and myocardial fibrosis.It is suggested that the determination of the VG, especially of its angle, is of clinical significance to decide whether the ST-T changes of the clinical electrocardiogram are based on myocardial damage or not, because the importance of the VG was confirmed by comparison with histologic findings of the heart.
- 社団法人日本循環器学会の論文
- 1958-02-20