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Because single - chamber rate - adaptive atrial pacing leaves the patient exposed to the risk of future development of AV block and DDD pacing does not provide chronotropic support , it is likely that the new rate - adaptive dual - chamber ( DDDR ) devices will be used in a significant number of these patients . ( ABSTRACT TRUNCATED AT 250 WORDS )
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
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