Based on our results, there were no significant effects on P amplitude, but in P duration obvious changes were seen with the use of high doses of amiodarone (25 mg/kg).Similar to P duration, increases in PR intervals were seen (Figures 8 and 9). The inductions of delay in P duration
and PR intervals were predictable because of amiodarone’s direct effects on Na+, Ca2+, and potassium (K+) channels and heart automaticity (9,19,20). Furthermore, these alterations can be induced by amiodarone blocking effects on cardiac β-receptors because of its β-blocker propertie