THE STATIC ELECTROCARDIOGRAM OF ZOO-KEPT NAKED MOLE-RATS (HETEROCEPHALUS GLABER) UNDER ALFAXALONE-KETAMINE ANESTHESIA

The naked mole-rat (Heterocephalus glaber) has become a subject of interest in cardiovascular research due to its unique biological properties. However, the ECG of this species has not been thoroughly described. The objective of this study was to characterize the ECG of ten clinically healthy naked mole-rats. Each animal was anesthetized with ketamine and alfaxalone, and ECGs were recorded in sternal recumbency using a hexaxial lead system. ECG resembled those of other rodents with a median heart rate of 174 beats/min (range: 131-202 beats/min), positive Q wave, R wave, and S wave (QRS) complexes in lead II, and absence of an isoelectric ST segment. All P waves were low amplitude (range: 0-0.05 millivolts (mV)) and <40 milliseconds (ms) in duration (26-33 ms) while the median PR interval was 85 ms (76-100 ms). Peak R wave amplitudes ranged from 0.26-1.15 mV depending on filter settings and QRS complex durations were 26-44 ms. The QT intervals ranged from 168-254 ms. An arrhythmia characterized by sinus rhythm with first- and second-degree atrioventricular block was noted in one animal. Collectively, these results provide baseline values in clinically healthy naked mole-rats, which will be relevant to clinical and research situations.