the cardiac arrhythmias due to vagal tone ( sinus arrhythmia , sinus block , sinus arrest , sinus bradycardia , wandering pacemaker , first-degree av block , and second-degree av block ) that are found in resting horses are generally considered to be normal and generally do not require therapy .
C0003811
cardiac arrhythmias
C0003813
sinus arrhythmia