The Effect of Aging to T-wave Change Induced by Exercise
1975 Volume 12 Issue 6 Pages 394-399
Details
1975 Volume 12 Issue 6 Pages 394-399
The effect of aging to T-wave change induced by exercise was investigated. Subjects included 171 healthy volunteers of non-cardiac patients were normotensive (less than 160/95mmHg). They were divided into 3 groups, young-aged group (aged less than 39) included 31 male and 17 female subjects, middle-aged group (aged between 40-55) included 44 male and 32 female subjects and old-aged group (aged more than 56) included 30 male and 17 female subjects. Exercise test was performed by using bicycle ergometer. Frank's lead system was used for exercise electrocardiogram and 3 scalar tracings on X, Y and Z leads were recorded at a paper speed of 100mm/sec. The amplitude of T-wave was measured at every 20msec., starting at 100msec. from the beginning of the earliest Q-wave in 3 leads. Each instantaneous T vector at every 20msec. was obtained on frontal and horizontal planes and T-loop was constructed by connecting each instantaneous T vector on frontal and horizontal planes. The maximal T vector (T-max.) was measured spatially on the constructed T-loop before, during and after exercise. Systolic blood pressure was measured by cuff-method and left ventricular ejection time (ET) was measured from the right carotid pulse wave before and after exercise.
(1) There was no significant diffierence in T-max. at rest among 3 groups. T-max. was decreased by exercise in young-aged and middle-aged groups, but was increased in old-aged group.
(2) There was no significant difference in the heart rate response to exercise among 3 groups. The blood pressure response to exercise was significantly higher in old-aged group than in young-aged group. ET was shortend after exercise in all groups, but its shortening was less significant in old-aged group than in youngaged group.
(3) It was speculated that the heart rate increase induced by exercise mainly contributed to the decrease of T-max. in young-aged and middle-aged groups and the other hemodynamic changes induced by exercise such as the increase in blood pressure and the augumented myocardial contractile state possibly contributed to the increase of T-max. in old-aged group.
