健常成人の若年性T波(Persistent Juvenile T Wave Pattern)に関する研究

Persistent juvenile T wave patterns found in mass examination and in clinical cases were studied for the purpose of clarifying their significance. Persistent juvenile T wave patterns were classified into three types. Type I had negative T waves in lead V(1) only, Type II in lead V(1) and V(2) and Type III in V(1) to lead V(3) or V(4). During mass examinations, persistent juvenile T wave patterns were found in 243 cases (43.5%) of 558 male subjects. Of these, 15 (6.2%) were Type II, III. On the other hand they occurred in 547 (66.5%) of 823 female subjects. Of these, 86 (15.7%) were Type II, III. The incidence of each Type of persistent juvenile T wave pattern did not vary significantly with age, but Type II, III were relatively more frequent between 35 and 49 years of age. Persistnet juvenile T wave patterns were often positive in many cases in electrocardiograms (ECG) thaken from the same subjects 8 years after the first mass examination. Standard ECG's and Frank's system vectorcardiogram (VCG)'s were analysed in 116 clinical cases showing persistent juvenile T wave patterns. Transitional zone and electrical axis deviation in ECGs were almost normal in the persistent juvenile T wave pattern. The shape of the transverse T loop was mostly normal whereas the transverse QRS loop normally varied in shape. Clockwise rotation of the transverse T loop was observed in 15 of 116 clinical cases. The maximum magnitude of the T loop in VCG was significantly smaller in Type III than in Type I, II. Changes in the persistent juvenile T wave pattern on ECG and VCG were studied in 25 cases after administration of Propranolol. The negative T wave in ECG tended to become positive and the maximal T vector tended to become larger shifting towards anterior in VCG after administration of Propranolol. The persistent juvenile T wave pattern was observed more frequently in middle aged women and usually became normal after administration of Propranolol. These results suggest that increased sympathetic tone is one of the pathological mechanisms involoved in the persistent juvenile T wave pattern.