Changes

===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.

The aim is to control heart rate to a level that is less likely to result in haemodynamic compromise (rarely conversion to normal sinus rhythm).  

High-dose '''oral quinidine or electrical cardioversion''' can be used in primary atrial fibrillation cases to convert the heart back to sinus rhythm. This requires experienced personnel, general anaesthesia and special equipment.

'''Digoxin''' is usually the first line of therapy. Digoxin slows conduction through the AV node.  The goal is to keep the heart rate <150 bpm. Dogs should be re-assessed 5-7 days after starting Digoxin and serum Digoxin levels should be measured >8 hours post-administration.  If the heart rate remains high and the serum Digoxin level is within target range, a calcium channel blocker such as '''Diltiazem''' can be added. If compliance is good and finances are not limited, there may be additional benefit of an ACE inhibitor, Spironolactone and Omega-3 fatty acids. These help reverse structural remodelling and modulate pro-inflammatory cytokines that perpetuate arrhythmias.  

In '''cats''', '''diltiazem or atenolol''' are usually the drugs of choice. Digoxin can also be added if the heart rate is still high or there is evidence of heart failure.

In '''dogs''' with '''primary 'lone' AF''':

If '''electrical cardioversion''' is an option, start '''Amioderone'''. This increases the chances of remaining in sinus rhythm following cardioversion and some dogs may spontaneously convert to sinus rhythm with Amioderone alone. If electrical cardioversion is not an option and the rate is >150bpm then rate control is appropriate, using '''beta-blockers''' or '''Diltiazem'''. It is important to monitor these dogs for the development of structural cardiac disease, as AF may be seen in the occult phase of [[Dilated Cardiomyopathy|Dilated Cardiomyopathy]].

In '''rabbits''', '''digoxin''' has been used anecdotally to slow the heart rate.

In '''cats''', atrial fibrillation usually indicates advanced structural heart disease with atrial dilation and is associated with a poor prognosis. The first-line drug of choice is  '''Diltiazem'''.  

In all cases with concurrent severe heart disease and possibly '''congestive heart failure''', efforts to control the disease by using diuretics such as '''frusemide''' can be helpful in improving clinical signs. Calcium channel blockers and beta-blockers, both negative inotropes, should be used carefully in animals with myocardial failure.

 

In all cases with concurrent severe heart disease and possibly '''congestive heart failure''', efforts to control the disease by using diuretics such as '''Furosemide''' can be helpful in improving clinical signs. Calcium channel blockers and beta-blockers, both negative inotropes, should be used carefully in animals with myocardial failure.

== Prognosis ==

== Prognosis ==