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definitions

tachyarrhythmia

[tăk′ē-ə-rĭð′mē-ə]
n.
  1. An excessively rapid heartbeat accompanied by arrhythmia.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.