Use of vectorcardiography for the detection of +Gz-related cardiac pathology in miniature swine.

Vectorcardiograms were recorded from anesthetized, adult miniature swine 1-2 weeks before high sustained +Gz exposure and 2-6 h after exposure. Each +Gz run consisted of one 60-s exposure, respectively, to 3, 5, 7, and 9 +Gz, with 3 min rest between each +Gz plateau. The full range, from severe to minor, of +Gz-induced cardiac pathology was observed in this group of miniature swine. In spite of the large variation in the amount and degree of cardiac pathology, there were no post-exposure vectorcardiographic changes which might be diagnostic of +Gz-induced cardiac pathology. The results of this study indicate that vectorcardiography, performed after +Gz exposure, is not a reliable technique for detecting the presence of +Gz-induced cardiac pathology in miniature swine.