Selenium and the Electrocardiogram in the Dromedary Camel (Camelus dromedarius)

AbstractSelenium (Se) is an essential trace element with well-established roles in antioxidant defense, redox regulation, and cardiovascular function. Both Se deficiency and excess have been associated with myocardial dysfunction and electrocardiographic (ECG) abnormalities in several animal species, yet limited data are available in the dromedary camel (Camelus dromedarius). The present study investigated the relationship between Se status and cardiac electrical activity in a cohort of apparently healthy adult female camels. Twenty camels (age 9.8 ± 0.3 years; body mass 406 ± 7 kg) were studied. Se concentrations were measured in hair and blood serum using inductively coupled plasma mass spectrometry. ECG recordings were obtained in a modified base–apex configuration under standardised conditions, and multiple ECG parameters were quantified, including PR, QRS, QT, corrected QT (QTc), ST and RR intervals, heart rate, and short-term heart rate variability. Mean Se concentrations were 0.61 ± 0.05 mg kg-1 in hair and 133 ± 10 ng ml-1 in serum, values consistent with previously reported reference ranges for camels. ECG analysis demonstrated considerable inter-individual variability in waveform morphology and interval duration, with a mean HR of 54 ± 3 beats min-1. Occasional arrhythmias, including premature ventricular contractions and marked bradycardia, were observed in a small number of animals and excluded from summary analysis. Correlation analysis revealed no significant associations between Se concentrations in serum or hair and PR interval, QRS duration, QTc interval, or HR (|r| < 0.5 for all comparisons). These findings indicate that, in apparently healthy adult female camels with Se concentrations within physiological range, Se status is not associated with alterations in resting ECG parameters. The results suggest that Se-related electrophysiological effects reported in other species may be context-dependent and become clinically relevant primarily under conditions of Se deficiency, excess, or additional metabolic or oxidative stress.