Читать книгу Manual of Equine Anesthesia and Analgesia - Группа авторов - Страница 151

 Characterized by a resting HR > 50 beats/min.The RR intervals are normal (variations >20% are considered to be abnormal).The relationship between the P waves and QRS complexes is normal.

 May be due to excitement or exercise in the normal horse.

 The maximal HR is between 220 and 240 beats/min.

 Abnormal increases at rest occur with many extra‐cardiac as well as cardiac disease processes.Extra‐cardiac causes include external stimuli to the heart, and are often due to one or a combination of the following: pain, hypovolemia, toxemia, septicemia. The “drive” may be a need for increase blood flow.Tachyarrhythmias have many causes and may be multifactorial. The origin may be atrial (SA node‐related or extra‐nodal, such as atrial fibrillation), supraventricular tachycardia (SVT) or ventricular tachycardia (VT).