Heart diseases

Heart diseases in catsHeart disease in cats is relatively common.

One of the most challenging aspects of feline heart disease is that cats may not show any warning signs (such as exercise intolerance, coughing, weakness) until the process is very advanced. Untreated heart disease can lead to congestive heart failure and death.

The most common heart disease in cats is cardiomyopathy, often diagnosed as a heart murmur. These are often detected at a young age, during routine vaccinations.


  • Chest Radiographs (x-rays)

Chest radiographs are important components in the diagnosis of feline heart disease. A diseased heart will most often enlarge over time. In advanced stages, fluid may be detectable in the chest cavity (pleural effusion) or in the lungs themselves (pulmonary edema).

  • Electrocardiogram (EKG or ECG)

An electrocardiogram (EKG or ECG) is a tracing of the electrical activity of the heart. It documents heart rate and rhythm. In addition, subtle changes can occur in the shape of the ECG spikes that can reveal certain types of pathological changes in the heart. It is a rapid and painless test that can be performed right in the veterinary office.

  • Echocardiogram

An echocardiogram, also known as a cardiac ultrasound exam, is one of the most advanced and sensitive tests for determining the presence of heart disease in animals. It is painless and generally does not require sedation. The technique uses sound waves to actually visualize the heart in action. From this exam, the dimensions of each heart chamber can be determined.

  • Sinus rhythm and sinus tachycardia

In normal healthy cats, a normal heart rate of 140 beats per minute is normal. Also, there is usually a normal sinus rhythm is defined as having regularly spaced P waves (<10% P-P variation), and for every P wave, there is a corresponding QRS complex followed by a T wave on an ECG. Once a heart rate exceeds 200 beats per minute, a sinus tachycardia is more appropriate.

  • Sinus bradycardia

Sinus bradycardia is defined as a heart rate below 120-140 beats per minute.

  • Sinus arrhythmia

Sinus arrhythmia is any abnormal ECG rhythm in cats, where there is a gradual variation in P-P intervals that exceeds 10%, which is often associated with respiration. It is often associated with diseases that affect vagal nerve tone, including intracranial disease, elevated intraocular pressure (e.g. glaucoma) and primary respiratory disease.

Common heart diseases of cats

Aortic (Sub-aortic) stenosis Double-outlet right ventricle Pericardial effusion Third degree AV block
Atrial fibrillation Double-chambered right ventricle Peritoneal-pericardial diaphragmatic hernia Tricuspid valve dysplasia
Atrial septal defects Endocarditis Pulmonary artery stenosis Truncus arteriosus
Atrial standstill FIP-induced pericarditis Pulmonic valve stenosis Toxoplasma pericarditis
Atrial tachycardia Heart failure Renal failure Valvular endocardiosis
Atrioventricular septal defects Heartworm disease Second degree AV block Ventricular tachycardia
Aortic thromboembolism Hemoplasmas Sinus bradycardia Ventricular premature beats
Bacterial pericarditis Hyperthyroidism Sinus tachycardia Ventricular septal defect
Cardiomyopathy – dilated Hypertension Supravalvular mitral stenosis and cor triatriatum sinister Wolff-Parkinson-White Syndrome
Cardiomyopathy – hypertrophic Hyperthyroidism Supraventricular premature beats
Cardiomyopathy – restrictive Mitral valve dysplasia Supraventricular tachycardia
Chemodectoma Mediastinal lymphoma Tetralogy of Fallot
Chylous effusion Myocarditis Patent ductus arteriosus
Dissecting aneurysm Pericardial cysts

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