Medical Dictionary

extrasystole

noun ex·tra·sys·to·le \-ˈsis-tə-(ˌ)lē\

Medical Definition of EXTRASYSTOLE

:  a prematurely occurring beat of one of the chambers of the heart that leads to momentary arrhythmia but leaves the fundamental rhythm unchanged—called also premature beat
ex·tra·sys·tol·ic \-sis-ˈtäl-ik\ adjective

Browse

How to use a word that (literally) drives some people nuts.
Test your vocab with our fun, fast game
Ailurophobia, and 9 other unusual fears