[Determination of the best place for electrodes and study of electrocardiographic parameters of the base-apex lead in horses and cattle]

ABSTRACT

Since the beginning of the introduction of electrocardiograph in the Veterinary Medicine specially for large animals, invetsigators realized the difficulties of electrodes attachment to the various parts of the limbs and the effects of limbs position and their movement on the ECG. For solving these problems and for finding a monitoring lead many research works have been carried out in different countries. At last, a base-apex lead was suggested. Reviewing the veterinary literatures shows that the position of the negative electrode of this lead has been reported differently by different workers. Thus a research was carried out on 10 horses and 10 cattle in order to standardize the electrode position. 15 points on 3 lines [above, middle, and below] on the left side of the neck of each animals was marked and electrode was attached to each position and then ECG was recorded. Comparing ECG recorded from each position from 10 horses and 10 cattle showed that the best place is point C4 [Fig 1.], that is, the middle of the neck above the jugular furrow. Thus, it is suggested that whenever this lead being used, the negative electrode is attached to C4 and the positive electrode on the cardiac area on the fifth intercostal space caudal to the point of the elbow joint. By using this lead the electrocardiogram was recorded from 50 adult healthy horses and 50 cattle. The electrocardiographical parameters including; heart rate, ECG congiurations [P, QRS, T], ECG ampitudes [P, QRS, T] and ECG intervals [P, P-R, QRS, Q-T, T] were measured and presented in Tables. These parameters can be used whenever this lead is used. Furthermore, ECG recorded from this lead is not affected by limb position and limb movements and it presents a very good and high amplitude ECG waves. So, this lead is suitable as a monitoring lead and for studying cardiac arrhythmias in large animal