Section: Information In-depth
Normal heart rhythm is initiated from the sinoatrial (SA or sinus) node, which is located in the right upper chamber (atrium) of the heart. While abnormalities of the sinus node are typically a consequence of other disorders, such as thyroid problems, primary sinus disease is common and may lead to a type of arrhythmia known as sick sinus syndrome. Other atrial arrhythmias arise outside the SA node. Among the most serious of these is atrial fibrillation. Arrhythmias arising from the ventricles may also be serious. Venticular arrhythmias include premature ventricular contractions and ventricular tachycardia. Serious arrhythmias may lead to cardiac decompensation and acute or chronic heart failure. Some arrhythmias worsen to the point of fibrillation and eventually the absence of any heartbeat (asystole).
Cardiac arrhythmias may involve a very low heart rate (potentially as low at 40 beats per minute), termed bradycardia; a very fast heart rate (potentially over 300 beats per minute in a cat), termed tachycardia; or simply an erratic heart beat. Numerous different types of arrhythmias may occur. Some of the more common ones include:
Atrial fibrillation
Atrial tachycardia
Ventricular escape rhythm
Ventricular premature complex
Ventricular tachycardia
Ventricular fibrillation
First degree heart block
Second degree heart block
Third degree heart block
Often, cardiac arrhythmias are associated with underlying heart disease caused by conditions such as hypertrophic cardiomyopathy, congestive heart failure, dilated cardiomyopathy, or congenital cardiac defects. In addition, there are a variety of other diseases or events that can cause cardiac arrhythmias, including:
Hyperthyroidism (overactive thyroid gland)
Chronic lung disease
Anemia
Overdose of certain medications such as digoxin, narcotics, xylazine
Administration of anesthetic agents
High or low blood potassium
Tumors of the heart
Trauma
Toxicity, such as chocolate poisoning
Urinary obstruction
Smoke inhalation
Head trauma
Hypothermia
Fear
Excitement
Pain
Low blood pressure (hypotension)
Diseases of the spleen
Severe infections
Related Articles
-
1
Electrocardiogram in Cats
An electrocardiogram (EKG) is a test done to record the electrical activity of the heart and is done by attaching small contact electrodes to the limbs and body.
» Read More
-
2
Hyperthyroidism in Cats
If your adult cat suddenly begins to lose weight despite a voracious appetite, he may have a problem with the hormone produced by the thyroid gland. You should probably get your pet to a veterinarian to...
» Read More
-
3
Atrial Fibrillation in Cats
In atrial fibrillation the normally coordinated electrical activity in the upper heart chambers, the right atrium and left atrium, is lost. The muscle of these chambers begins to wiggle like a "bag full...
» Read More
-
4
Dilated Cardiomyopathy in Cats (DCM)
Dilated cardiomyopathy (DCM) is a myocardial disease, which is disease of the heart muscle that is characterized by dilation (enlargement) of the cardiac chambers and markedly reduced muscle contraction....
» Read More
-
5
Hypertrophic Cardiomyopathy in Cats
Hypertrophic cardiomyopathy (HCM) is a condition characterized by thickening of the main pumping chamber of the heart. Eventually, HCM often leads to congestive heart failure.
» Read More
