A NEW EXPERIMENTAL-MODEL OF ISOLATED MYOCARDIAL ISCHEMIC-INJURY - ECGFINDINGS OF ACUTE ISOLATED RIGHT-VENTRICULAR ISCHEMIC-INJURY

A new experimental porcine model for creating selective ischemia of a specific part of the myocardium while the rest of the myocardium remai ns free of ischemia has been used to study the electrocardiographic (E GG) changes deriving from selective ischemia of the right ventricular (RV) free wall. A patch was stitched to the ventricle to produce selec tive myocardial ischemic injury. In a preliminary study of nine pigs, selective ischemia of the left ventricular free wall in five and of th e RV free wall in four animals was induced, and a post mortem dye inje ction was performed to evaluate blood flow in the area of ischemia. In an ECG study of 20 pigs, the baseline ECG was recorded with use of th e standard leads I-III, aVR, aVL, and aVF, left precordial leads (V-1- V-6), and leads V-4R, V-3H, and V-4H and 1 hour after inducing ischemi a, the ECG study was repeated. Our experimental model produced ischemi c injury in which the location and surface area were known antemortem. In the 20 pigs, ST-segment changes were recorded in leads V-1-V-3, V- 3H, and V-4H. In only four pigs (20%) was ST-segment elevation recorde d in lead V4R The results show that the ECG signs of selective ischemi a of the RV free wall may imitate the signs of anterior or anterolater al infarction of the left ventricle. In this study, elevation of the S T-segment in lead V4R was not pathognomonic of for RV ischemia. This m odel is a new tool for studying hemodynamic and ECG changes of selecti ve univentricular or biventricular ischemic injury.