Determination of Kinetic, Structural and Functional Changes in the Hearts of Dogs with Experimentally Introduced Myocardial Infarction Using M-Mode and 2-D Echocardiography


Abstract: In this study, the kinetic, structural and functional changes of the ventriculus in dogs with myocardial infarction introduced experimentally were examined using M-Mode and two dimensional (2-D) echocardiography. 21 healthy, mixed-breed dogs of both genders (16 females and 5 males) and of various ages were used in this study. Different coronary arteries were ligated in each dog with silk sutures and the dogs were grouped accordingly: left distalis descending coronary artery (Group I, n=7), right distalis descending coronary artery (Group II, n=7) and both left and right distalis decending coronary artery (Group III, n=7). All the dogs were examined using echocardiography prior to the study. After the coronary arteries were ligated, this was repeated at 2, 4, 8 and 12-hour intervals for seven days. Wall motion abnormalites were observed in areas of infarction (left ventricle posterior wall = LVPW) in addition to irregularities in mitral valvule (MV) movements 2 hours after coronary ligation in Group I Increases were observed in the left ventricle (LV) end-systolic diameter (EDS) and end-diastolic diameter (EDD), circumference (C) and area (A); and also int he right ventricle (RV) EDS and RVEDD, RVC, RVA, RV systolic volumes (SV) and diastolic volumes (DV) in Group I, whereas the LV shortening fraction (SF), RVSF and ejection fraction (EF) (p<0.05) decreased. Two hours after ligation, it was observed that there were wall motion abnormalities in areas of infarction (Interventricular septum=IVS) in Group II. Although in these dogs, RVEDS, RVEDD, RVC, RVA, RVSV and RVDV increased significantly, it was determined that RVSF and RVEF decreased (p<0.05). Examination of the dogs in Group III, 2 hours after ligation, revealed wall motion abnormalities in areas of infarction (both LVPW and IVS) MV movements. While LVEDS, LVEDD,LVSV, LVDSV, RVC, RVA, RVSV and RVDV incerased, a decrease was observed in LVSF, RVSF and RVEF (p<0.05). In conclusion, in addition to the kinetic, structural and functional changes induced in the heart with acute myocardial infarction it was concluded that in both LV and RV apical infarction, particularly RV, there was functonal disorder in both ventricles.

Keywords: Echocardiography, Myocardial Infarction, Dogs

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