3825
In addition , the excitability of the cardiac conduction system was depressed preferentially in the atrioventricular nodal region of hearts from barium - exposed rats .
 Chemical: barium
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: barium