arythmia (??r?ðm??; e??r?ðm??) n a variant spelling of arrhythmiaCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014arrhythmia, arhythmia, arythmia, arrythmiaany abnormality in the rhythm of the heartbeat. ? arrhythmic, arhythmic, arythmic, arrythmic, adj.See also: Heart-Ologies & -Isms. Copyright 2008 The Gale Group, Inc. All rights reserved.