Feline Cardiac Arrhythmias Study Guide

Overview and Clinical Importance

Cardiac arrhythmias in cats represent a critical diagnostic and therapeutic challenge in veterinary cardiology. Unlike dogs, cats have a predominantly sympathetically-driven heart rate, making sinus arrhythmia an uncommon and often pathological finding. Feline arrhythmias are frequently associated with underlying hypertrophic cardiomyopathy (HCM), the most common acquired heart disease in cats, affecting approximately 10-15% of the feline population.

Recognition of arrhythmias is essential for the NAVLE, as these conditions can lead to sudden cardiac death, arterial thromboembolism (ATE), and congestive heart failure (CHF). The ECG remains the gold standard for arrhythmia diagnosis, though interpretation in cats requires understanding of species-specific peculiarities, including small QRS amplitude and wide variability in mean electrical axis.

Normal Feline ECG Parameters

Understanding normal feline ECG values is fundamental for recognizing pathological rhythms. Cats have several unique ECG characteristics that differ from dogs, including smaller waveform amplitudes, shorter intervals, and a wider normal mean electrical axis range (0 to +160 degrees).