DIELECTRIC SPECTROSCOPY FOR MONITOR OF INTRA OPERATIVE MYOCARDIUM

点击翻译按钮获取中文摘要

We have already examined dielectric properties and reported the peak value of the loss tangent (tan delta m), as a primary parameter to represent the dielectric properties, of myocardium was correlated with ischemic injury of the myocardium. We examine whether tan delta m with dielectric spectroscopy can evaluate myocardial viability instantaneously and predict cardiac function after reperfusion. Seven isolated porcine hearts were immersed in 4ﾟC saline solution. We measured tan delta m tof myocardium. After various period of preservation (145 to 350 minutes), heterotopic cardiac transplantation was performed, respectively. Change in tan delta m was compared with left ventricular contractility after reperfusion. During the preservation, tan delta m (5.08(]SY.+-。[)1.05) decreased gradually until transplantation. In 120 minutes after reperfusion, recovery of Ees of left ventricle from baseline was ranging from 51.0% to 90.7%. Recovery of LV Ees (%baseline) was correlated with the tan delta m at the end of preservation (range 2.56 to 4.49) (r<@D12@>D1=0.867, p<0.01). We examined seven clinical cases (59.7(]SY.+-。[)21.2 y.o.). We measured tan delta m of myocardium during ECC.During aortic clamping, tan delta m (5.31(]SY.+-。[)0.72) decreased gradually until declamp. We used corrected formulas of temperature based on 37ﾟC for avoiding temperature effect. Minimum value in tan delta m during aortic crossclamping was compared with recovery of left ventricular work index (%LVWI) from baseline in 120 minutes after ECC (DOA 3or5 gamma). %LVWI was correlated with minimum value in tan delta m (range 3.70 to 4.59) (r<@D12@>D1=0.960, p<0.01). The dielectric spectroscopy might evaluate myocardial viability instantaneously and predict the cardiac function after reperfusion subsequently. The tan delta m may be useful parameter for evaluation of myocardial viability instantaneously and prediction of the ventricular contractility after reperfusion.