Normal vector magnetocardiogram. II. Effect of constitutional variables.
The effects of age, sex, height, weight, and dimensions of the thorax on the vector magnetocardiogram (VMCG) were studied in 290 normal subjects. The effect of sex on 141 VMCG parameters was tested with the Mann-Whitney U test, and the effects of age and body dimensions on the male and female subjects were tested with the Kruskal-Wallis H test. Similar analyses were applied for a comparison of the vector electrocardiogram (VECG) in a subgroup of 200 normal subjects. Sex had the most pronounced effect on the VMCG, a total of 58% of the instantaneous time-normalized QRS and T amplitude parameters were significantly (P < .01) different in men and women (47% for the VECG). In women, the absolute VMCG amplitudes were, on average, about 60% of those in men. In the VECG, the corresponding portion was about 85%. In men and women, 50 and 26% of the time-normalized amplitude parameters, respectively, were significantly (P < .01) affected by age; the main effect was a decrease in most VMCG amplitudes with increasing age. In the VECG, the corresponding effect was not as statistically significant. The effect of constitutional variables of the body on the VMCG and VECG was, in most cases, not statistically significant. Multiple correlation analysis showed that the five noncardiac factors together explained, at most, 16 and 28% of the variability in the instantaneous, time-normalized QRS amplitudes for men and women, respectively. In the VECG, these figures were 13 and 18%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Nousiainen
J
J
Ragnar Granit Institute, Tampere University of Technology, Finland.
Oja
S
S
Malmivuo
J
J
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001827:Body Height; D001835:Body Weight; D005260:Female; D005544:Forecasting; D006801:Humans; D016014:Linear Models; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D013909:Thorax / Q000033:anatomy & histology; D014672:Vectorcardiography / Q000379:methods*