Atrial Fibrillation & Atrial Flutter

Dog: common

Cat: uncommon

Horse: common; male>female; Standardbreds and Draft horses are most affected

Cattle: common; especially dairy cattle

Atrial Fibrillation: Occurs when many ectopic waves of depolarisation spread throughout the atria. While the atria fail to contract some of the disorganized depolarization waves are conducted through the AV node reaching the ventricles. As a result the ventricles have a rapid, irregular rate.

Atrial Flutter: A rare unstable arrhythmia consisting of rapid atrial rate and abnormal atrial depolarization. Atrial flutter is an arrhythmia that cycles between atrial fibrillation and sinus rhythm.

Causes

Atrial pathology, pathology of other systems, electrolyte imbalances, drug interactions

ECG Appearance: lack of P waves (atrial fibrillation); small f waves (atrial flutter)

Treatment

Treat all underlying conditions

Dog & Cat: digoxin +/- diltiazem or +/- propranolol; quinidine or diltiazem (used in animals without cardiac failure or enlargement)

Horse: quinidine sulfate or treat congestive heart failure (furosemide, digoxin etc.)

Cattle: quinidine sulfate; Digoxin (given first if tachycardic)