Basic feasibility studies on interventional cardiology in horses

Abstract

In horses, both physiological and pathological cardiac arrhythmias occur. Pathological cardiac arrhythmias can develop primarily as conductive disorders or secondarily as a result of changes in the structure of the heart, metabolic and endocrine disorders, systemic inflammation, low blood pressure, bleeding, anaemia, ischaemia, toxicosis, and various drug effects. The examination of arrhythmias is particularly important due to the haemodynamic changes that result from them (reduced blood pressure, decreased flow or perfusion) and the development of electrical instability (fibrillation, sudden cardiac death). The cardiac rhythm of horses has been studied using electrocardiography (ECG) since the 1910s. The first electrocardiogram obtained from a horse was published in 1913. From the 1960s, with the aid of radiotelemetry devices, it became possible to record electrocardiograms from horses during exercise and, by the 1980s, extensive knowledge was available regarding the physiological and pathological rhythm disorders in horses. Besides pharmacological and transvenous electrical cardioversion (TVEC), interventional methods have been developed in horses lately. There are a lot of technical issues that cause difficulties in the adaptation of human interventional methods in horses. The main differences are the larger size of the equine thorax and heart and the dissimilarities in the electrical properties of the conduction system in the heart.