Supraventricular Tachycardia. 
The term paroxysmal supraventricular tachycardia encompasses a heterogeneous group of arrhythmias with different electrophysiologic characteristics.  Knowledge of the mechanism of each supraventricular tachycardia is important in determining management in the office, at the bedside, and in the electrophysiology laboratory.  Paroxysmal supraventricular tachycardias have an abrupt onset and offset, typically initiating and terminating with premature atrial ectopic beats.  In the acute setting, both vagal maneuvers and pharmacologic therapy can be effective in arrhythmia termination.  Catheter ablation has revolutionized therapy for many supraventricular tachycardias, and newer techniques have significantly improved ablation efficacy and decreased periprocedural complications and procedure times.