| Objective:The aim of this study is to evaluate the the accuracy and practicability of evaluating the viable myocardium in swine model of acute myocardial infarction by CARTO voltage mapping and calculating the myocardial fractional flow reserve (FFRmyo) and zero flow pressure (Pzf). The present study focuses on the following issues:1)To establish the swine model of acute myocardial infarction by coronary occlusion with angioplasty balloon. The viable myocardium in those swines model were detected by CARTO voltage mapping and compared with the result of using TTC dying to evaluate the accuracy of CARTO voltage mapping.2) To calculate myocardial fractional flow reserve (FFRmyo) value before and after the swine model of acute myocardial infarction established, to judge the viable myocardium using TTC dying and to evaluate the the viable myocardium by FFRmyo after establishment of swine model of acute myocardial infarction.3) To calculate coronary artery zero flow pressure (Pzf) value before and after the swine model of acute myocardial infarction established, to observe the relationship between the viable myocardium area and Pzf value after established the swine model of acute myocardial infarction and to evaluate the practicability of predicting the viable myocardium area by calculating Pzf value.Methods:Part one:13 swines, after received anesthetic tracheal cannula, the distal of left anterior descending coronary arteries were blocked up by angioplasty balloon for 60～90 minutes. The model of acute myocardial infarction were established by coronary occlusion with angioplasty balloon. The viable myocardium in those swines model were detected by CARTO voltage mapping after reconstruction of the left ventricle using CARTO valtage mapping system. Taken out of those swines' hearts after executed them, sliced the cardiac muscle and dyed with TTC to detect viable myocardium then compared with the result of CARTO voltage mapping to evaluate the the accuracy of the result of CARTO voltage mapping. Part two:13 swines, received coronary arteriongraphy after anesthetic tracheal cannula, measured their aortic pressure using guiding catheter and measured their distal pressure of left anterior descending (LAD) coronary arteries using coronary artery pressure wire, then calculated the myocardial fractional flow reserve (FFRmyo). Placed the coronary artery angioplasty balloon in the distance of LAD to blocked the blood flow 60-90 minutes to establish the model of acute myocardial infarction. Calculated FFRmyo repeadly after withdrawn the balloon. Observe the change of FFRmyo. Taken out of those swines'heart after executed them, sliced the cardiac muscle and dyed with TTC to detect the viable myocardium. Evaluated the prognosis value of detecting the viable myocardium using the index of FFRmyo<0.75. Part three:13 swines, received coronary arteriongraphy after anesthetic tracheal cannula, measured their aortic pressure using guiding catheter and measured their distal of LAD blood flow velocity uuing coronary artery Doppler wire, then calculated the coronary artery zero flow pressure (Pzf). Placed the coronary artery angioplasty balloon in the distance of LAD to blocked the blood flow 60-90 minutes to establish the model of acute myocardial infarction. Calculated Pzf value again after withdrawn the balloon. Observe the change of Pzf. Taken out of those swines'heart after executed them, sliced the cardiac muscle and dyed with TTC to detect the viable myocardium. Calculated the percent ratio of viable myocardium to the whole left ventrcular myocardium using Image tool 3.0 after the swine model of acute myocardial infarction established. Drawed the percent ratio of viable myocardium-Pzf coordinate graph and observed the relationship between them.Results:Part one:(1)13 swines'LAD were all obstructed by angioplasty balloon.2 swines died of ventricular fibrillation after the coronaries were occluded 45 and 65 minutes respectively. The other 11 swines were successfully established models of acute myocardial infarction by occlusion of the LAD that proved by ST segment arch elevation in the body electrocardiagram in the course of LAD occlusion and left ventricular angiography after withdrawn the balloons when there were locomotor disturbance in the left ventricular myocardium. (2) The swines'left ventricle was divided into 16 segments, there were 176 segments in 11 swines. The two results detected by CARTO and TTC dyeing had good concordance, Kappa=0.816, P<0.001. (3) Taken the result of TTC dyeing as standard, The sensitivity, specificity and accuracy rate detected by CARTO voltage mapping was 71.8%,96.5 and 93.8% respectively.Part two and three:1)11 out of 13 swines were successfully established models of acute myocardial infarction by coronary occlusion and finished the calculation of FFRmyo and Pzf before and after established the swine model of acute myocardial infanction.2) After the model of acute myocardial infarction established, all FFRmyo<0.75 and the FFRmyo of the models of acute myocardial infarction were less than before (P<0.001). The result of TTC dying proved that the viable myocardium existed in all swines model of acute myocardium infarction which provided a testimony to prove the theory that the viable myocardium could be predicted by FFRmyo<0.75.3)After the model of acute myocardial infarction established, the Pzf value of the models of acute myocardial infarction were more than before (P=0.038). the Pzf value increased with the percent ratio of viable myocardium to the whole left ventrcular myocardium decreased. Drawn the scatter diagram, the percent radio of viable myocardium were negative correlation with Pzf after the model of acute myocardial infarction established.regression equation was y=-0.764x+98.10, the correlation coefficient r=-0.879, P<0.001.Conclusions:The conclusion of this study can be drawn from the following,1) The swine model of acute myocardial infarction can be established successfully by coronary occlusion with angioplasty balloon.2) The viable myocardium can be detected by using CARTO voltage mapping, which provided with a new way to detcet viable myocardium after acute myocardial infarction.3) FFRmyo<0.75 is probably a criterion that can detect the viable myocardium and Pzf is an index that can predict the extent of viable myocardium after acute myocardial infarction.
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