AV Nodal Reentrant Tachycardia

Definition

AV nodal reentrant tachycardia is a type of supraventricular tachycardia (SVT) characterized by a reentrant circuit involving the atrioventricular (AV) node. This abnormal heart rhythm is caused by a circular electrical impulse that repeatedly travels through the AV node, leading to a rapid and regular heartbeat.

5 Must Know Facts For Your Next Test

1. AV nodal reentrant tachycardia is the most common type of SVT, accounting for approximately 60% of all SVT cases.
2. The reentrant circuit in AV nodal reentrant tachycardia typically involves two pathways within the AV node: a fast pathway and a slow pathway.
3. Calcium channel blockers, such as diltiazem and verapamil, are effective in terminating and preventing episodes of AV nodal reentrant tachycardia.
4. Patients with AV nodal reentrant tachycardia often experience sudden-onset, regular, and rapid heartbeats that may last for minutes to hours.
5. Radiofrequency ablation, a minimally invasive procedure, is a highly effective treatment option for individuals with recurrent or drug-resistant AV nodal reentrant tachycardia.

Review Questions

• Explain the mechanism behind AV nodal reentrant tachycardia and how it differs from other types of supraventricular tachycardias.
  • AV nodal reentrant tachycardia is characterized by a reentrant circuit that involves the AV node, specifically the fast and slow pathways within the node. This reentrant circuit allows the electrical impulse to repeatedly travel through the AV node, leading to a rapid and regular heartbeat. This mechanism is distinct from other types of supraventricular tachycardias, which may involve different anatomical structures or pathways, such as accessory pathways or ectopic foci in the atria.
• Discuss the role of calcium channel blockers in the management of AV nodal reentrant tachycardia, and explain how they are thought to be effective in this condition.
  • Calcium channel blockers, such as diltiazem and verapamil, are considered first-line pharmacological agents for the management of AV nodal reentrant tachycardia. These medications work by selectively blocking calcium channels in the AV node, which can disrupt the reentrant circuit and terminate the tachycardia. Calcium channel blockers are effective in AV nodal reentrant tachycardia because they slow conduction and prolong the refractory period within the AV node, making it more difficult for the electrical impulse to repeatedly travel through the reentrant circuit and sustain the arrhythmia.
• Evaluate the role of radiofrequency ablation in the treatment of recurrent or drug-resistant AV nodal reentrant tachycardia, and discuss the potential advantages and considerations of this procedure compared to long-term pharmacological management.
  • Radiofrequency ablation is a highly effective treatment option for individuals with recurrent or drug-resistant AV nodal reentrant tachycardia. During this minimally invasive procedure, a catheter is used to deliver radiofrequency energy to the slow pathway within the AV node, effectively disrupting the reentrant circuit and eliminating the arrhythmia. The primary advantage of radiofrequency ablation is that it can provide a long-term, potentially curative solution, eliminating the need for lifelong pharmacological management with its associated side effects and potential for drug interactions. Additionally, ablation can be particularly beneficial for patients who are unable to tolerate or do not respond well to antiarrhythmic medications. However, the procedure does carry a small risk of complications, and the decision to pursue ablation should be made in close consultation with a cardiac electrophysiologist, weighing the potential benefits and risks for the individual patient.

Related terms

Supraventricular Tachycardia (SVT): A group of abnormal heart rhythms that originate above the ventricles, often characterized by a rapid and regular heart rate.

Reentrant Circuit: A circular pattern of electrical impulses that repeatedly travel through a specific pathway, leading to a sustained arrhythmia.

Atrioventricular (AV) Node: A group of specialized cells located between the atria and ventricles that act as a relay station, allowing electrical impulses to travel from the atria to the ventricles.