Electrocardiogram pattern of some exotic breeds of trained dogs: A variation study

AIM: The present study has been conducted to evaluate the variation in electrocardiogram (ECG) parameters among different trained breeds of dogs (viz. Labrador, German Shepherd, and Golden Retriever) used for security reasons. MATERIALS AND METHODS: The ECG was recorded by single channel ECG at a paper speed of 25 mm/s and calibration of 10 mm=1 mV. The recordings were taken from all the standard bipolar limb leads (Lead-I, II, and III) and unipolar augmented limb leads (Lead-aVR, aVL, and aVF). RESULTS: Heart rate was found to be highest in Labrador and lowest in German Shepherd. P-wave duration was maximum in Golden Retriever breed and lowest in Labrador. Maximum amplitude of P-wave was found in Labrador followed by German Shepherd and Golden Retriever. There was significantly (p<0.05) higher values of PR interval in German Shepherd compared to other breeds. The variation in QRS duration, ST segment duration, T-wave duration, and T-wave amplitude was found to be non-significant among breeds. Inverted T-waves were most common in Golden Retriever and German Shepherd, whereas positive T-waves were found in Labrador. There was significant (p<0.05) variation in mean electrical axis of QRS complex among different breeds and it ranges from +60° to +80°. CONCLUSION: The present study provides the reference values for different ECG parameters to monitor the cardiac health status among Labrador, German Shepherd, and Golden Retriever breeds.