Electrocardiographic studies on arrhythmia in dogs

Abstract

Study entitled “Electrocardiographic Studies on Arrhythmia in Dogs” was conducted in eight dogs. It was conducted to study the incidence and to delineate the etiopathogenesis and clinical manifestation of arrhythmias in dogs. Out of 11,230 canine patients, cardiac disease observed in 0.22 per cent and arrhythmia observed in 0.07 per cent of cases. The parameters observed were signalment, history and detailed clinical examination, electrocardiography, radiography, echocardiography, haematology and serum biochemical assays. Dog between the groups of seven to ten years were more frequently affected and it was more commonly observed in males. Arrhythmia was recorded more in Dobermann Pinschers followed by German Shepherd, Boxer, Cocker Spaniel and Mongrel. The types of arrhythmia observed in the present study included supraventricular tachycardia, ventricular premature complexes, first degree atrio- ventricular block and right bundle branch block. In supra ventricular tachycardia typical ECG findings in lead II were morphologically abnormal P waves and very short P-R intervals. In ventricular premature complexes, typical ECG findings were wide bizarre QRS complexes and T waves directed opposite to QRS complexes. Prolonged P-R interval was the typical finding in first degree atrio-ventricular block. In right bundle branch block typical ECG findings were prolonged QRS complexes with prominent slurred S waves. The frequently observed clinical signs of arrhythmia were lethargy, weakness, exercise intolerance, cough and dyspnoea. Syncope and cardiac cachexia were also observed. Pulse deficits and haemic murmurs were also noticed in a few cases. Arrhythmias were noticed in association with cardiac diseases and secondary to renal diseases. Radiography and echocardiography were useful to find out cardiac chamber enlargement and mitral valve insufficiency. Haematological and serum biochemical values did not show any significant changes in arrhythmias.