Description of the Disease
AVNRT is a type of supraventricular (above the ventricles) tachycardia.
Causes of the Disease
The cause of atrioventricular nodal reentrant tachycardia (AVNRT) is a congenital division ('dissociation') of the AV node into 2 conducting channels, which have a common start and end, and different electrophysiological properties.
Similar to WPW syndrome, AVNRT is characterized by the re-entry mechanism, whereby an excitation impulse begins to circulate in a circle, resulting in tachycardia.
Learn More about WPW SyndromeSymptoms of the Disease
Patients with AVNRT experience sudden episodes of rapid heartbeat, lasting from several minutes to several hours (less frequently), which also end suddenly; episodes may be accompanied by dizziness, shortness of breath, pre-fainting states, and chest pain.
Diagnostics of the Disease
Specific changes on resting ECG are absent. The diagnosis is made based on the ECG recorded during the tachycardia episode and confirmed by electrophysiological study.
Treatment of the Disease
Drug treatment for AVNRT is ineffective. To terminate episodes of rapid heartbeat, 'vagal maneuvers' can be used (holding breath on deep inhalation with abdominal muscle tension, placing face in cold water, pressing on the eyeballs, etc.).
The only effective and radical treatment method is radiofrequency catheter ablation (RFCA), during which the 'pathological' conducting channel is eliminated.
Learn More about Radiofrequency Catheter AblationPrognosis of the Treatment
Atrial fibrillation may occur in half of patients with AVNRT, which usually resolves after AVNRT catheter ablation.