1013
Because the adrenergic nervous system influences cardiac arrhythmias and myocardial infarction can directly affect sympathetic innervation in the heart , we investigated the role of the sympathetic nervous system on reentry in the canine heart 4 days after infarction .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
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