PSVT is a term used to denote intermittent supraventricular tachycardia other than atrial fibrillation, atrial flutter and multifocal atrial tachycardia (AT). The major causes are atrioventricular reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), and sinoatrial node reentrant tachycardia (SNRT).