[A clinical study of examples of variability and instability of fixed sections of canine EKGs]

Study in ECGs of a clinical collection of 45 dogs (15 dogs without heart disease and without sedation or anesthesia, 15 dogs with acquired and congenital heart disease without sedation or anesthesia, 15 dogs premedicated and anesthetised and all dogs except one without heart disease). Especially studied were the parts which are known in the ECG of the dog as variable and labile (ST-segment, ST-segment-junction and the T-wave). In the group of premedicated and anesthetised dogs a curved and arched ST-segment was more often observed as in comparison to the other two groups. On the other hand the ECG evaluations showed that in all studied groups independent of the status of the heart many similar or equal configurations of the variable and labile parts of the ECG were observed.