Evaluation of myocardial viability during simple cold storage with the use of electrical properties in broad frequencies.
BACKGROUND
The purpose of this study ws to determine whether myocardial viability during simple cold storage can be monitored from alteration of electrical properties of the preserved heart.


METHODS
Twelve anesthetized dogs underwent rapid cardiac extirpation and were preserved in simple cold storage ( 4 degree C). They were divided into two groups according to preservation solutions. Groups S and U were preserved in saline and University of Wisconsin Solutions, respectively. The loss-tangent (Tan delta) in dielectric spectroscopy was analyzed on serial measurements of electrical properties of the preserved heart with an electrical impedance meter. Myocardial specimens were taken for myocardial adenosine triphosphate measurement with high-performance liquid chromatography and myocardial water content. We investigated the correlations among myocardial adenosine triphosphate, myocardial water content, and Tan delta.


RESULTS
The maximum value of Tan delta corresponds to a frequency fT which ranged from 5 to 10 kHz in both groups and maximum Tan delta gradually decreased during preservation in both groups. Myocardial adenosine triphosphate in group U was significantly higher than that in group S. The ratio of measured adenosine triphosphate and maximum Tan delta to the preischemic values during preservation were expressed as percentage of adenosine triphosphate and percentage of maximum Tan delta. There was close correlation between myocardial percentage of adenosine triphosphate and percentage of maximum Tan delta during preservation in both groups. Myocardial water content in group S increased during preservation but did not increase in group U. There was no correlation between myocardial water content and percentage of maximum Tan delta during preservation. Tan delta function were used to characterize the electrical properties of biologic tissue and were clearly associated with ischemic histologic damage of tissues.


CONCLUSIONS
Therefore measurement of electrical properties in broad frequencies of the preserved heart may be feasible as a monitor of graft viability in a minimally invasive method.
Ishikawa
M
M
First Department of Surgery, Gifu University School of Medicine, Japan.
Hirose
H
H
Sasaki
E
E
Bando
M
M
Mori
Y
Y
Murakawa
S
S
D000241:Adenosine; D000255:Adenosine Triphosphate / Q000378:metabolism; D000493:Allopurinol; D000818:Animals; D001834:Body Water / Q000378:metabolism; D002314:Cardioplegic Solutions; D003080:Cold Temperature; D004285:Dogs; D004553:Electric Conductivity; D005978:Glutathione; D006321:Heart / Q000502:physiology; D006329:Heart Conduction System / Q000502:physiology; D016027:Heart Transplantation / Q000502:physiology; D007328:Insulin; D009206:Myocardium / Q000378:metabolism; D009926:Organ Preservation; D019188:Organ Preservation Solutions; D011887:Raffinose; D014022:Tissue Survival
D002314:Cardioplegic Solutions; D007328:Insulin; D019188:Organ Preservation Solutions; C055206:University of Wisconsin-lactobionate solution; D000493:Allopurinol; D000255:Adenosine Triphosphate; D005978:Glutathione; D000241:Adenosine; D011887:Raffinose