Tissue Doppler echocardiographic examinations at rest and after exercise in horses with atrial fibrillation
Gewebedopplerechokardiopgraphische Untersuchung bei Pferden mit Vorhofflimmern in Ruhe und nach Belastung
Gehlen H, Iversen C, Stadler P
DOI: 10.21836/PEM20090102
Year: 2009
Volume: 25
Issue: 1
Pages: 11-16
Within this Study 35 warmblood horses were examined. 15 of the horses showed atrial fibrillation. 20 warmblood horses without pathologic findings of the heart were taken as control. A clinical examination, electro- and echocardiographic examination was performed with all horses of the study. In addition to the standard examinations the myocardium was analysed using Tissue Doppler echocardiography. The myocardial velocity of the left ventricle free wall and of the septum was evaluated in the short axis of the heart. Following velocities points were measured: peak systolic velocity (Vs), peak velocity at the isovolumetric contraction (Vic), early diastolic velocity (Ve) and late diastolic velocity (Va). The myocardial velocities were evaluated at rest and after a standard lunge exercise. To measure the myocardial velocities the heart was examined in the short axis from the right side of the horse directly underneath the level of the mitral valves at the high of the papillary muscles with a maximal depth of 28 cm, an angle of 70° und 60 bps. The regions of interest were the free wall of the left ventricle and the septal wall. The exercise examination was performed after a standard lunge exercise (5 minutes of walk, 10 minutes of trot and 5 minutes canter). The horses with atrial fibrillation showed a highly significant dilatation of the left atrium (p < 0,0001) and ventricle (p < 0,005). The right atrium (p < 0,001) and right ventricle (p < 0,001) were also significant enlarged in comparison to the horses without pathologic findings of the heart. In the evaluation of the myocardial velocities obtained with the tissue velocity imaging some of the horses with atrial fibrillation didn’t showed any late diastolic wave (n=12). In the cases a late diastolic wave could be detected the amplitude of the waves were significant lower then the late diastolic waves of the horses without pathologic findings of the heart. In contrast to the late diastolic wave, the remaining measured velocities were significant higher in the horses with atrial fibrillation in comparison to the horses without pathologic findings of the heart. After exercise the peak systolic velocities of the horses with atrial fibrillation were significant higher then in the horses without pathologic findings of the heart