Arrhythmias are abnormalities of cardiac impulse, conduction, rate and or regularity. Many cardiac arrhythmias are begin and clinically in significant and require no specific therapy but some arrhythmias may cause sever clinical signs or lead to cardiac arrest and sudden death. The purpose of this study was to review the prevalence of cardiac arrhythmias in cats which were referred to Pet hospital of Vet. Faculty of Tehran University. Sinus Tachycardia and Ventricular Premature Complexes were the most common in cats referred. From 10 June 1999 to 17 Oct. 1999, the Pet hospital admitted 283 cats. Review of 112 electrocardiographic samples of these cats indicates percentage of various arrhythmias. The arrhythmias observed are as following:
Sinus tachycardia (7 1%), VPC (21.4%), Sinus bradycardia :7.1%), Wandering pacemaker (2/4%), Sinus arrhythmia (2.4%), A trial Fibrillation (2.4%), Silent atrium (2.4%) escape rhythm (2.4%) and Ventricular tachycardia (2.4%).