AVKnotenReentry

AVKnotenReentry refers to a specific type of cardiac arrhythmia involving abnormal electrical activity within the atrioventricular (AV) node, a critical junction in the heart’s conduction system. The AV node is responsible for transmitting electrical impulses from the atria (upper heart chambers) to the ventricles (lower heart chambers), regulating heart rhythm. In AV node reentry tachycardia (AVNRT), an abnormal electrical circuit forms within or around the AV node, causing rapid, repetitive electrical signals that disrupt normal heart rhythm.

This condition is classified as a type of supraventricular tachycardia (SVT), meaning the abnormal rhythm originates above the heart’s ventricles. AVNRT is typically benign but can cause palpitations, chest discomfort, shortness of breath, or even syncope (fainting) in severe cases. It is most common in young adults and individuals with a history of heart conditions, though it can affect people of any age.

The exact mechanism of AVNRT involves two distinct pathways within the AV node: a fast pathway and a slow pathway. Normally, impulses travel through the fast pathway. However, in AVNRT, an impulse may inadvertently activate the slow pathway, creating a reentry circuit. When the impulse returns to the fast pathway, it can trigger another cycle, leading to rapid, repetitive heartbeats.

Diagnosis often involves an electrocardiogram (ECG), which may show a narrow QRS complex and characteristic patterns like pseudo-RBBB (right bundle branch block) morphology. Additional tests, such as an electrophysiology study (EPS), may be used to confirm the diagnosis and identify the specific reentry circuit.

Treatment typically begins with vagal maneuvers (e.g., carotid sinus massage or the Valsalva maneuver) to temporarily restore normal rhythm. If recurrent, medications like beta-blockers, calcium channel blockers, or antiarrhythmic drugs may be prescribed. For persistent or severe cases, catheter ablation—a minimally invasive procedure—can permanently block the abnormal pathway, effectively curing AVNRT in most patients. Prognosis is generally excellent, with ablation offering long-term success in over 90% of cases.