AVNRT: Difference between revisions

'''AV Nodal Re-entry Tachycardia (AVNRT)''' or Atrial-Ventricular Nodal Re-entry Tachycardia is a [[SVT|supra-ventricular arrhythmia]], and more precisely, a nodal arrhythmia. AVNRT is the most frequently occurring form of regular tachycardia. More females than males have signs of AVNRT. The ratio is approximately 3:1. Symptoms are bouts of fast heart rates with sudden onset. Neck vein palpitations can be prominent (the 'Frog Sign'). Termination is often possible with valsalva manouevres (blowing on wrist, squatting, carotid sinus massage) or medication (adenosine, verapamil, diltiazem), or electrocardioversion. An AVNRT is a regular rhythm with a rate of 180-250 /min. A condition for AVNRT to occur is that 2 electric pathways occur in and around the AV node (a slow paced and a fast paced pathway). That gives way to the ccurrence of re-entry.

*'''Typical ANVRT''' (also described as common ANVRT or slow-fast ANVRT):  The impulse travels over the slow pathway towards the ventricles and returns via the fast pathway to the atria. The retrograde P wave (or Atrial echo) shows up at the end of the QRS. 90 % of all patients with ANVRT are diagnosed with typical ANVRT. Spontaneous termination of typical AVNRT often occurs in the fast pathway (terminates with a QRS on the ECG), induced termination with carotid sinus massage or adenosine results in termination in the slow pathway (terminates with retrograde P on ECG).

*The remaining cases of ANVRT patients are diagnosed with a form of ANVRT that is even more rare. This form of ANVRT is '''slow/slow ANVRT''' (The impulse follows a complex route through the AV node and the surrounding area). Only 4 % of all patients diagnosed with ANVRT have slow/slow ANVRT.