Abnormal Heart Rhythm in Cats

A slower-than-normal impulse rate in the sinus node is medically referred to as sinus bradycardia (SB) or sinoatrial node (SAN) or Abnormal Heart Rhythm in Cats. The sinus node initiates an electrical impulse within the heart, triggering the heart to beat or contract. In most cases, slow sinus electrical impulses are benign, and they may even be beneficial. Meanwhile, it can also cause loss of consciousness, if it is brought about by an underlying abnormal condition that disrupts the cardiac autonomic nerves, which act as the heart’s control system. The SB is less common in cats as compared to dogs. However, the rate of the heartbeat will depend on the environment the size of the animal.

Abnormal Heart Rhythm in Cats – Symptoms, Diagnoses, and Treatment

Abnormal Heart Rhythm in Cats

Symptoms and Types

The owner of the cat may observe no signs in the cat if it is very active or engaging in athletic training. However, the sinus bradycardia (heartbeat slower than 120 beats per minute, although it depends on the pet’s environment and size) is most apparent when the cat is at rest. There are some other common symptoms associated with sinus bradycardia may include:

  • Seizures
  • Lethargy
  • Exercise intolerance
  • Episodic muscle incoordination (ataxia)
  • Loss of consciousness
  • Excessively slow breathing (hypoventilation), especially under anesthesia


  • Hypothermia
  • Intubation
  • Oversedation
  • Sleep
  • Athletic Conditioning (this cause is not uncommon in athletic cats)
  • Underlying diseases e.g., neurologic, respiratory, and gastrointestinal disorders.


The Veterinarian performs a detailed physical exam of the cat. He/she will also take into account the background history of symptoms, cat’s overall condition, and activity level.

The veterinarian will conduct a complete blood profile, including a chemical blood profile, total blood count, and urinalysis. Its result may indicate the presence of a substance that might be causing a slowed heart rate in the cat and tests will show the deficiencies in the blood. They will also provide possible clues for kidney failure. The veterinarian may also go towards the X-rays and ultrasound to visually examine the cat’s internal organs for abnormalities in the heart, kidney, or other related organs.

Another option is an electrocardiogram (EKG) recording that can be used to examine the electrical currents in the heart muscles, and it may reveal any abnormalities in cardiac electrical conduction that underlies the heart’s ability to contract and beat. An initial 24 hours of heart monitoring may be indicated to conclude a diagnosis.


The underlying disease will determine the treatment and therapeutic approaches for SB, the severity of clinical signs, and the ventricular rate. However, many cats show no clinical signs, and they require no as such treatment.

If the cat is in critical condition, it must be treated as an inpatient, where intravenous fluid therapy can be administered. The restrictions on activity are not recommended unless the cat has symptomatic SB that is related to structural heart disease, then exercise restraint will be approved until the surgical or medical intervention can resolve the issue.

Living and Management

The veterinarian will recommend further monitoring, depending on the final diagnosis. Signs, if present, should determine with proper correction of the underlying causative condition. Meanwhile, the overall long-term prognosis varies with the nature of structural heart disease i.e., in the case of one present. For example, the treatment of symptomatic SB with the permanent pacemaker generally provides an excellent prognosis for rhythm control.


In the end, team Pets Trouble says that the Abnormal Heart Rhythm is one of the sensitive problems in cats. It is among those diseases whose symptoms are not easy to recognize. After reading this article, one can have an idea about the necessary preventive measures and treatment ideas.

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