Clinically silent atrial dissociation in a dog.

A Labrador retriever, presented for a routine yearly wellness exam, shows on ECG a normal sinus rhythm with first degree atrioventricular blockade and atrial dissociation (AD). A detailed cardiologic examination was performed including thoracic radiography, echocardiography and blood pressure measurement, all of which were considered normal. The dog described in this current report was re-examined several times over the subsequent 2 years and no clinical signs of heart failure, heart disease or other diseases were recognized, the AD appears to have been benign.