Atrial Tachycardia Versus Atrial Fibrillation in Horses

First the mechanisms of atrial tachycardia and atrial fibrillation are explained, followed by their pathophysiological effects. Current knowledge about the AT substrate will be given including data from gross anatomy, histology, immunohistochemistry of ‘hot spots’ and myocardial sleeves. Tips and tricks will be given to differentiate AT from AF in daily clinical practice: auscultation characteristics, ECG characteristics and tips how to place the electrodes, use of heart rate graphs during exercise tests, use of wearable devices and smartphone devices. Next the importance of differentiating both rhythms in horses will be highlighted: prognosis and treatment options of AT are different from AF. AT is more likely to show recurrence when treated with conventional methods such as quinidine sulphate or transvenous electrical cardioversion. Finally, most recent data from diagnosis and treatment of AT by 3D electro-anatomical mapping and transcatheter radiofrequency ablation are provided. This new technique allows identification of the underlying mechanism (focus or reentry) and the precise anatomical location. Treatment by radiofrequency ablation not only terminates the arrhythmia, it also reduces the risk of recurrence. During the presentation both techniques will be explained at a level which fits both practitioners and veterinary cardiologists. The presentation is richly illustration by video’s.