Changes

===Cattle===

===Cattle===

Signs generally relate to the underlying disease process, which in cows can range from '''gastrointestinal diseases''' such as a left-displaced abomasum, to uterine torsion.

Signs generally relate to the underlying disease process, which in cows can range from '''gastrointestinal diseases''' such as a [[LDA|left-displaced abomasum]], to uterine torsion.

===Small animals===

===Small Animals===

Patients with primary atrial fibrillation are usually asymptomatic, but may present with exercise intolerance.

Patients with primary atrial fibrillation are usually asymptomatic, but may present with exercise intolerance.

Other signs are generally related to the underlying disease process or '''congestive heart failure'''. There may be a history of coughing, dyspnoea, tachypnoea, exercise intolerance, episodes of syncope..

Other signs are generally related to the underlying disease process or [[:Category:Heart Failure|'''congestive heart failure''']]. There may be a history of coughing, dyspnoea, tachypnoea, exercise intolerance, episodes of syncope.

== Diagnosis ==

== Diagnosis ==

==Treatment==

==Treatment==

===Horse===

===Horse===

In horses where the condition is found without concurrent heart disease, treatment is with the drug '''quinidine sulphate'''. The necessity for this depends on the requirement of the horse to perform work, as horses can be retired or used as brood mares and can live a normal life with the condition.

In horses where the condition is found without other concurrent heart disease, treatment is with the drug '''quinidine sulphate'''. The necessity for this depends on the requirement of the horse to perform work, as horses can be retired or used as broodmares and can live a normal life with the condition.

Quinidine sulfate acts by prolonging the effective refractory period. The horse should be given quinidine sulphate concurrently with '''digoxin''', which will have been started two days prior to commencing quinidine sulphate. Quinidine sulphate should be given every two hours by stomach tube until conversion to sinus rhythm, or until six doses have been given. There are some severe '''side effects''' which can occur with this treatment and they include ventricular tachycardia, [[:Category:Colic in Horses|colic]], diarrhoea and hypotension.

Quinidine sulfate acts by prolonging the effective refractory period. The horse should be given quinidine sulphate concurrently with '''digoxin''', which will have been started two days prior to commencing quinidine sulphate. Quinidine sulphate should be given every two hours by stomach tube until conversion to sinus rhythm, or until six doses have been given. There are some severe '''side effects''' which can occur with this treatment and they include [[Ventricular Tachycatdia|ventricular tachycardia]], [[:Category:Colic in Horses|colic]], diarrhoea and hypotension.

There is a greater success with conversion in young horses and when conversion is attempted shortly following the onset of the arrythmia. If the arrythmia has been present for more than 4 months, therapeutic success is much less common and there is a higher recurrence rate.

There is a greater success with conversion in young horses and when conversion is attempted shortly following the onset of the arrythmia. If the arrythmia has been present for more than 4 months, therapeutic success is much less common and there is a higher recurrence rate.

Horses can also develop atrial fibrillation secondary to '''cardiac disease''', such as mitral valve insufficiency, tricuspid valve insufficiency, or any acquired or congenital disease leading to atrial hypertrophy. Horses will usually develop '''congestive heart failure''' and have a resting tachycardia. These underlying conditions should be diagnosed and the congestive heart failure treated with diuretics and inotropes. These horses will have a poor prognosis for return to function and treatment is mainly to slow progression of disease.

Horses can also develop atrial fibrillation secondary to '''cardiac disease''', such as [[Mitral Valve Dysplasia|mitral valve insufficiency]], [[Tricuspid Valve Dysplasia|tricuspid valve insufficiency]], or any acquired or congenital disease leading to atrial hypertrophy. Horses will usually develop '''congestive heart failure''' and have a resting tachycardia. These underlying conditions should be diagnosed and the congestive heart failure treated with diuretics and inotropes. These horses will have a poor prognosis for return to function and treatment is mainly to slow progression of disease.

===Cattle===

===Cattle===

Cattle are not usually treated with an antiarrythmic drug as the heart will '''revert to sinus rhythm''' following the correction of the underlying abdominal disorder.

Cattle are not usually treated with an antiarrythmic drug as the heart will '''revert to sinus rhythm''' following the correction of the underlying abdominal disorder.

===Small animals===

===Small Animals===

In '''dogs''', '''digoxin''', is usually the first line of therapy in slowing conduction through the AV node. The goal is to keep the heart rate between 140 and 160 beats per minute. If the heart rate remains high, a calcium channel blocker such as '''diltiazem or a beta-blocker''' should be used as well.

In '''dogs''', '''digoxin''', is usually the first line of therapy in slowing conduction through the AV node. The goal is to keep the heart rate between 140 and 160 beats per minute. If the heart rate remains high, a calcium channel blocker such as '''diltiazem or a beta-blocker''' should be used as well.

== Prognosis ==

== Prognosis ==

In '''horses''', the likelihood of it remaining converted after the treatment depends on the duration of the condition before treatment; if it was diagnosed less than three months before treatment then it is more likely the treatment will be effective. Prognosis is poor if atrial fibrillation is caused by an underlying heart condition.

In '''horses''', the likelihood of the rhythm remaining converted after the treatment depends on the duration of the condition before treatment; if it was diagnosed less than three months before treatment then it is more likely the treatment will be effective. Prognosis is poor if atrial fibrillation is caused by an underlying heart condition.

In '''cattle''', prognosis depends on the underlying gastrointestinal condition and the treatment options chosen by the farmer.

In '''cattle''', prognosis depends on the underlying gastrointestinal condition and the treatment options chosen by the farmer.

{{Learning

{{Learning

|flashcards = [[Rabbit Medicine and Surgery Q&A 02]]

|flashcards = [[Rabbit Medicine and Surgery Q&A 02]]<br>[[Equine Internal Medicine Q&A 12]]

}}

}}

<br>

<br>

Mazzaferro, E. (2011) '''Blackwell's five minute veterinary consult clinical companion: ECC''' ''Wiley-Blackwell''

Mazzaferro, E. (2011) '''Blackwell's five minute veterinary consult clinical companion: ECC''' ''Wiley-Blackwell''

{{review}}

{{review}}

[[Category:Altered_Supraventricular_Impulse_Formations]]

[[Category:Altered_Supraventricular_Impulse_Formations]]

[[Category:Cardiovascular Diseases - Cattle]][[Category:Cardiovascular Diseases - Horse]]

[[Category:Cardiac Diseases - Cattle]][[Category:Cardiac Diseases - Horse]][[Category:Cardiac Diseases - Cat]][[Category:Cardiac Diseases - Dog]]

[[Category:Expert_Review]]

[[Category:Expert_Review]]