Tachyarrhythmias Tachyarrhythmias have a rapid ventricular rate (> 100 beats / minute in resting adults); tachyarrhythmias may be divided into 4 groups, defined by the QRS complexes: Visibly regular vs irregular QRS complexes Narrow vs wide QRS complexes Irregular, narrow QRS complex tachyarrhythmias include the following 4 rhythms.