ELECTROCARDIOGRAPHIC CHANGES DURING CORONARY STENT PLACEMENT IN SWINE

The ECG changes that occurred during coronary stent placement in healthy swine were investigated in order to clarify the effect of surgical manipulation on the electrical activity of the heart. The experiment was performed on nine female swine weighing 80+/-2.3 kg under halothane anaesthesia. Eighteen coronary stents were implanted into both left anterior and right coronary artery of the animals using a guiding catheter and transfemoral approach. Multi parameter patient monitor was used to examine closely the ECG changes during the procedure. Direct stent implantation was successful in 7 of 9 cases and these animals recovered uneventfully. The first two animals died 7-9 hours after surgery because of thrombosis of the stents. Initially all of the seven investigated animals showed sinus rhythm. During the procedure two of the animals developed ventricular arrhythmias. One type of seen electrocardiographic abnormalities was single ventricular premature complexes (VPCs) appearing with an irregular pattern. The other abnormality observed was bigeminia that was preceded by multiple VPCs. These ECG changes occurred when the tip of the catheter was advanced too deep through the aorta and touched the endocardium. ECG changes during coronary stent placement in healthy swine were closely related to the operative technique, but anesthetic agents may contribute to arrhythmias. 6F angiographic catheters did not cause coronary artery occlusion and myocardial ischemia in 80 kg pigs.