Dual atrioventricular nodal non-re-entrant tachycardia.

Dual atrioventricular nodal non-re-entrant tachycardia (DAVNNT), also known as 'double fire', has recently received more attention since it was demonstrated to mimic more common arrhythmias such as atrial premature beats, atrial fibrillation, and ventricular tachycardia. This is important, since mistaken differential diagnoses and the resulting therapeutic decisions have severe consequences for affected patients. DAVNNT is characterized by conduction characteristics of the atrioventricular (AV) node that leads to a double antegrade conduction of one sinoatrial nodal activity via the slow and fast AV nodal pathways. As a result, the most significant hint from an electrocardiogram (ECG) is a P wave followed by two narrow QRS complexes. Although DAVNNT is rather a rare arrhythmia, it now appears to be more common than previously thought. To date, 68 cases including 3 small single-centre observational studies accumulated over the last 5 years have demonstrated the feasibility and safety of radiofrequency catheter ablation for DAVNNT. Catheter ablation treats this arrhythmia effectively by modifying or eliminating slow pathway function. Here, we review the current state of DAVNNT knowledge systematically and address current challenges presented by this 'ECG chameleon from the AV node'.