Atrial Flutter

Atrial Flutter



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Definition


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.



Synonym(s)


Auricular flutter



Epidemiology



Species, Age, Sex




• Large breeds are more susceptible than small breeds.


• Rarely occurs in ponies.



Risk Factors




• Similar to atrial fibrillation (AF)


• Underlying cardiovascular pathology leading to atrial dilation or atrial myocardial structural lesions


• Atrial premature contractions


• Electrolyte disturbances


• High vagal tone



Clinical Presentation



Disease Forms/Subtypes




• Spontaneous, sustained atrial flutter occurs on rare occasions in horses. In most animals, the arrhythmia quickly turns into AF.


• Atrial flutter is frequently encountered during quinidine treatment in horses, as an intermediate rhythm between AF and sinus rhythm.



History, Chief Complaint




• Performance loss


• Occurs during quinidine treatment



Physical Exam Findings




• Irregular pulse


• Auscultation


• Irregular rhythm (normal rate at rest)

• Rapid atrial sounds rarely detected


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.

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Jul 24, 2016 | Posted by in SMALL ANIMAL | Comments Off on Atrial Flutter
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