Master Atrioventricular Nodal Reentrant Tachycardia with Picmonic for Medicine

Atrioventricular nodal reentrant tachycardia is also known as AVNRT. The ventricular rate of atrioventricular nodal reentrant tachycardia is around 140-280 bpm.

Atrioventricular nodal reentrant tachycardia rhythm is regular.

The P wave is often hidden within the QRS complexes. This wave is typically present in the slow-fast AVNRT, a common feature in 80-90% of AVNRT cases. In the other type of AVNRT, known as fast-slow AVNRT, P waves may be visible retrograde after the QRS complex. This type accounts for approximately 10% of AVNRT cases.

The absence of a P wave in atrioventricular nodal reentrant tachycardia results in the unseen PR interval.

The QRS complex measures as <0.12 seconds in atrioventricular nodal reentrant tachycardia. In slow-fast AVNRT, a pseudo r' wave can be seen in lead V1, and pseudo-S waves can be seen in leads II, III, or aVF.

Vagal maneuvers can be effective in stopping AVNRT in hemodynamically stable patients. These maneuvers stimulate the vagus nerve and may include carotid sinus massage (by pressing the carotid sinus in the neck) and the Valsalva maneuver, which involves bearing down or holding one's breath to increase pressure in the chest by exhaling against a closed airway.

Adenosine is the most common modality used if the vagal maneuvers have failed twice to restore the patient's rhythm. It works by blocking or slowing the AV node, which can effectively prevent an AVNRT event from occurring. Other modalities may include beta-blockers and calcium channel blockers.