Cardiac Arrhythmia in Dogs and Cats
📝 Summary
Cardiac arrhythmia is an abnormal heart rhythm from a fault in the heart's pacing or conduction, showing as an irregular pulse and heart sound. Some forms are harmless, while others cause weakness, collapse, or sudden death. Treatment targets the underlying disease plus rhythm control.
1 Symptoms
A normal heartbeat arises from the sinus node, the heart’s natural pacemaker. An arrhythmia appears when pacing or conduction is disturbed, as in congenital conduction syndromes, acquired heart disease, toxicity, or electrolyte imbalance.
Some animals show no harm; others die suddenly. Mild cases have abnormal heart sounds and pulse, tire easily, and recover slowly after exercise. Severe cases show weakness, rapid breathing at rest, marked irregular rhythm, dullness, cramps, drowsiness, and collapse, even sudden death. Listening and feeling the pulse reveal an irregular beat; after death there may be no obvious visible change.
2 Causes and Transmission
Arrhythmias arise when the heart’s pacemaker or conduction pathways malfunction. Causes include congenital conduction abnormalities, acquired heart muscle disease, poisoning, and disturbances of electrolytes such as potassium.
Some arrhythmias are secondary to another illness, while a few have no identified cause.
3 Diagnosis
A veterinarian detects an irregular pulse and heart rhythm on exam, then uses an electrocardiogram (ECG) to classify the arrhythmia and its origin.
Blood tests for electrolytes and thyroid function, plus ultrasound of the heart, find the underlying disease that drives the abnormal rhythm.
4 Treatment
Treatment manages the underlying disease and, based on the diagnosis, adds rhythm-control medication. A veterinarian selects anti-arrhythmic drugs matched to the specific rhythm disturbance.
Diet and activity are adjusted to support the heart, and any electrolyte or toxin problem is corrected. Severe conduction failure may need advanced care under specialist direction.
5 Prevention and Home Care
Manage known heart disease and avoid toxins or electrolyte upset; keep pets at a calm, appropriate activity level. Regular cardiac checkups help catch rhythm problems early.
Seek urgent care for fainting, sudden weakness, or a very fast or slow pulse, and give any prescribed heart medication exactly as directed.
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