Electrocardiogram and His bundle electrogram of Japanese monkeys (Macaca fuscata).

Electrocardiogram (ECG) was taken from Macaca fuscata in the supine position under secobarbital anesthesia. The ECGs were recorded in the leads of standard (I, II, III), augmented unipolar limb (aVR, aVL, aVF) and unipolar chest (V4R, V1, V2, V3, V4, V5, V6,). The ECG was similar to that of humans as well as the monkeys of other species in their general patterns and the voltage of each wave (P, Q, R, S, T), though the heart rate was considerably different. The direction of T wave was consistent with that of human ECG. The PR, QRS and QT intervals and the duration of P wave were in good agreement with those of monkeys of other species, and amounted to about 50% of those of human ECG. His bundle electrogram (HBE) was recorded with a tripolar electrode catheter inserted into the right ventricle via the femoral vein, and PA, AH, HV and PV intervals were measured. All of the values were also approximately 50% and PV intervals were measured. All of the values were also approximately 50% of those reported in human HBE. Such short time intervals observed in Macaca fuscata may be due to a smaller heart size of the monkey as compared to the human's. The measurements of ECG and HBE reported in the present study may be used as a normal reference in ECG and HBE of Macaca fuscata under anesthesia. The study suggests that the Macaca fuscata is useful as an animal model to investigate the repolarization process of human ECG.