The Surface Electrocardiogram in Unanesthetized Adult Domestic Cats (Felis catus)

The purpose of this study was to describe and suggest normal surface electrocardiographic values of the unanaesthetized indigenous domestic cat (Felis catus), reared commonly as a household pet throughout India. Twenty cats, aged between 1–4 years, averaging 2.2 kg body weight (ranging from 1.1–3.1 kg) were chosen randomly for the study. Recordings were made using standard limb leads (I, II and III) and augmented limb leads (aVR, aVL and aVF) in right lateral recumbency with a single channel electrocardiograph. The heart rate, normal ECG waves, complexes and intervals were recorded during the study. A sinus rhythm was observed in all animals selected and studied. No ectopic complexes or arrhythmias, nor any abnormalities in electrocardiographic patterns were recorded. Estimated mean heart rate in the cat was 233.4 ± 2.34 beats per minute. The P-R interval and Q-T interval observed in the cat occupied approximately 31 and 69% respectively, of the total electrical cycle. The results of the present study give a fair approximation of the normal ECG values described earlier for the cat. The observed results would be helpful as a guideline to the clinician for perceiving the abnormal electrographic parameters in the domestic cat when diagnosing specific cardiac abnormalities during their clinical presentations.