In this study, the electrocardiographic parameters necessary to determine cardiac enlargements and to establish and distinguish such complaints from each other in the early stage in dogs with circulatory problems were assessed. The material of the study consisted of 33 dogs 1.5-15 years of age with cardiac enlargements determined from 140 dogs suspected of having cardiac disease based on clinical, radiographic and electrocardiographic analyses. In these dogs, 12 cases of left atrial hypertrophy (LAH), 6 cases of right atrial hypertrophy (RAH), 22 cases of left ventricular hypertrophy (LVH) and 1 case of right ventricular hypertrophy (RVH) were determined. The results of electrocardiographic records showed lengthening in P wave duration in left atrial hypertrophy (0.07±0.01 mm/sec), increase in P wave amplitude in right atrial hypertrophy (0.51±0.07 mV), increase in R wave amplitude in left ventricular hypertrophy (3.07±0.57 mV), and increase in S wave amplitude in right ventricular hypertrophy (2.8 mV). In vectorcardiographic analysis, the mean electrical axis of the QRS complex was determined to be 75.83±20.16 degrees in left atrial hypertrophy, 76.5±10.43 degrees in right atrial hypertrophy, 51.76±36.29 degrees in left ventricular hypertrophy and -98 degrees in right ventricular hypertrophy. It was observed that cardiac enlargements can be easily detected via the I and aVF leads of electrocardiography. In this way, it was determined that atrial enlargements can be easily detected by increases in P wave duration or amplitudes of electrocardiography, and ventricular enlargements can be easily detected by increases in R or S waves amplitudes.
GÖNÜL, REMZİ; OR, MEHMET ERMAN; and DODURKA, TAMER (2002) "Electrocardiographically Determination of Cardiac Enlargements in Dogs," Turkish Journal of Veterinary & Animal Sciences: Vol. 26: No. 4, Article 26. Available at: https://journals.tubitak.gov.tr/veterinary/vol26/iss4/26