Dielectrical spectroscopy of canine myocardium during acute ischemia and hypoxia at frequency spectrum from 100 kHz to 6 GHz

We studied dielectrical properties of canine myocardium during acute ischemia and hypoxia using dielectrical spectroscopy method at frequency spectrum from 100 kHz to 6 GHz. This study was conducted on a group of six canines with acute ischemia and seven canines with hypoxia. Hypoxia (10% for 30 min) decreases myocardial resistance (/spl rho/), while the dielectrical permittivity (/spl epsi/') of the myocardial tissue remains statistically unchanged. Acute ischemia for 2 hr causes significant frequency-dependent changes in both /spl epsi/' and /spl rho/ of myocardial tissue. Myocardial resistance increases, while the sign and amplitude of changes in the myocardial /spl epsi/' are frequency and time dependent. These observations open up an opportunity for assessing the properties of myocardial tissue using dielectrical spectroscopy as well as noninvasively with the help of imaging methods based on electrical impedance and microwave tomography.