Справжня передсердна тахікардія

This narrow QRS tachycardia arises from an abnormal automatic focus or intra-atrial reentry. P waves precede the QRS complexes; it is often a long RP interval tachycardia (PR < RP) but may be a short RP tachycardia (PR > RP) if atrioventricular nodal conduction is slow.