Supraventricular arrhythmia characterized by rapid, regular atrial depolarizations that are caused by a self-sustaining, single-circuit reentry mechanism. The atrial rate is approximately 180 to 250 contractions per minute with an irregular ventricular response.
Physical Exam Findings
Etiology and Pathophysiology
• A single-circuit reentry is induced by atrial premature beats and results in a regular, rapid atrial rate independent of the sinus node.
• Irregular conduction of the atrial impulses through the atrioventricular (AV) node results in an irregular ventricular response.
• Chronic atrial flutter leads to a loss of atrial contractile function caused by tachycardiomyopathy.
• Generally, no or only mild underlying cardiac pathology is present. Horses with severe cardiac disease generally do not develop atrial flutter but rather AF.