Definition of atypical AVNRT
AVNRT, reentrant tachycardia
Atrio-ventricular node reentrant tachycardia (AVNRT) was diagnosed by fulfillment of standard criteria during an electrophysiologic study with atrial/ventricular pacing maneuvers: 1-Typical (slow-fast) AVNRT was characterized by AH/HA ratio > 1, and HA ≤ 70 ms, 2-Atypical AVNRT was defined by delayed retrograde atrial activation with HA > 70 ms. If the AH was < 200 ms and the AH < HA, the atypical AVNRT was diagnosed as fast-slow. If AH > 200 ms and AH > HA, the atypical AVNRT was diagnosed as slow-slow.