A new apparatus and method for measuring the myocardial electrical impedance spectrum

Myocardial electrical impedance (MI) is correlated to the vitality of the tissue. The authors describe a new apparatus and method for measuring MI in a clinically applicable way. The apparatus is embedded-controller-based and connects to the heart via two cardiac pacing leads. Impedance spectra are obtained from fast Fourier transform analysis of a current impressed on the myocardium and the resultant voltage drop. New spectra are determined automatically in real-time succession. The impedance measurement is unaffected by electrode polarization. This apparatus has its greatest potential use in determining the need for and type of resuscitation following coronary artery graft surgery intraoperatively and monitoring the viability of cardiac transplant surgery postoperatively.<
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