Showing papers by "Joanna Dukes-McEwan published in 2003"

Long-term follow-up of dogs with patent ductus arteriosus.

Abstract: Postocclusion survival data from dogs with left-to-right shunting patent ductus arteriosus (PDA) was available from 80 dogs, diagnosed from 1990 to 2000. Of these, 37 had undergone a procedure to close the ductus and were re-evaluated at the time of this study; clinical data from the follow-up examination was compared with that from the original examination. Radiographically, the right ventricle remained apparently enlarged, and the aortic bulge associated with dilation of the descending aorta did not disappear after closure. On M-mode echocardiography, left ventricular chamber diameter in diastole and systole and left ventricular posterior wall in systole decreased significantly. Mitral endocardiosis was a common feature. Residual flow was evident in 46 per cent of the animals. Late closure occurred in 8 per cent of the dogs, and trivial recanalisation in 19 per cent. The maximum survival time postclosure was 168 months and, after non-occlusion, 114 months, suggesting that dogs with PDA follow an unpredictable course. However, there was a significant difference in survival times between the corrected and non-corrected group.

Peak mean myocardial velocities and velocity gradients measured by color M-mode tissue Doppler imaging in healthy cats.

Abstract: We sought to assess the feasibility of recording the myocardial velocity gradients (MVGs) and mean myocardial velocities (MMVs) measured by color M-mode tissue Doppler imaging (TDI) in the free wall of unsedated normal cats (n = 18) with a 74-MHz probe equipped to record TDI images The peak MVG and MMV values during the different phases of the cardiac cycle corresponded to certain color velocity patterns occurring in the left ventricular free wall (LVFW) Biphasic shifts were recorded in the tracings of both the MVG and MMV during early diastole (El and E2) as well as during the isovolumic relaxation (IVR) and isovolumic contraction (IVC) phases Stepwise regression analysis showed that age was the only significant predictor for the peak MVG values during the 2nd phase of early diastole (E2) (r = -079, r 2 = 063, and P <001) The peak late diastolic MVG values were associated positively with age (r = 050, r 2 = 025, and P <05) The peak MMV values showed a negative association with age during E2 (r = -071, r 2 = 050, and P <001) as well as during early systole (Se) (r = -055, r 2 = 030, and P < 05) and late systole (Sl) (r = -062, r2 = 039, and P <01) A positive association was found between age and the peak MMV values during late diastole (r = 054, r 2 = 029, and P <05) The MVG values showed cyclic variations consistent with wall thickness changes The accuracy of velocity determination and the spatial resolution of the system used were validated with a phantom To our knowledge, this study is the 1st report of the application of this technique to the myocardium of cats, providing insights into the physiology of myocardial motion It provides reference ranges of the peak MVG and MMV values for future studies of feline myocardial diseases