Читать книгу Manual of Equine Anesthesia and Analgesia - Группа авторов - Страница 152

 Type 1 (Mobitz type1, Wenckebach phenomenon)This is the most common type of second‐degree block in the horse.Progressive prolongation of the PR interval until a dropped beat occurs. The ECG shows a P wave not followed by a QRS complex.Often associated with increased vagal tone and is common with administration of α2 agonists.Normal sinus rhythm can be restored with this type of arrhythmia by exciting or exercising the horse to increase sympathetic tone and decreasing parasympathetic tone. Elevation of the HR above 60–80 beats/min may be required to resolve the block.

 Type 2 (Mobitz type 2)Regular PR interval and then sudden absence of a QRS after a P wave.Persistence of the heart block, despite exercising the horse to increase the sympathetic tone, may indicate a pathologic condition such as disease of the AV node, which is often the case for this type of block.