Approach Considerations
Rest, reassurance, sedation, and/or vagal maneuvers may terminate an attack of atrioventricular nodal reentry tachycardia (AVNRT). The successful management of an acute attack, however, depends on the symptoms, the presence of underlying heart disease, and the natural history of previous episodes.
In the presence of a wide-complex tachycardia, the institution of therapy should always follow a careful review of the patient's prior cardiac history, including left ventricular function and previous electrocardiograms (ECGs), which are helpful tools for defining the origin of the arrhythmia (ie, supraventricular vs ventricular).
The use of calcium channel blockers is contraindicated in patients with tachycardias of ventricular origin and may cause hemodynamic compromise and death.
Vagal maneuvers
To terminate AVNRT, try vagal maneuvers (eg, carotid sinus massage, exposure of the face to ice water, Valsalva maneuver) before initiating drug treatment. These maneuvers can also be tried after each pharmacologic approach. Vagal maneuvers are unlikely to work and should not be tried if hypotension is present. Sometimes, putting the patient in the Trendelenburg position facilitates termination with a vagal maneuver.
Direct-current synchronized cardioversion
Direct-current (DC) synchronized cardioversion is used to terminate an attack if the patient has hemodynamic compromise or if drug conversion fails and the patient continues to be symptomatic. However, DC cardioversion is rarely necessary for AVNRT.
Competitive atrial or ventricular pacing may be used if DC cardioversion is contraindicated (eg, if high doses of digitalis have been administered).
Diet
No specific recommendations or restrictions are necessary, but some patients' episodes are exacerbated by caffeine, theophylline, or theobromine in selected foods (coffee, tea, or chocolate, respectively). Alcohol may also be a trigger.
Activity
Advise the patient to rest during tachycardia, preferably in a supine position.
Consultations
Consultations include the following:
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Cardiologist
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Electrophysiologist
Transfer
Transfer to a facility capable of performing electrophysiologic studies and radiofrequency ablation may be needed.
Pharmacologic Therapy
Drugs that can be used to terminate an attack include adenosine, calcium channel blockers (eg, diltiazem, verapamil), beta-blockers, and digitalis.
Adenosine
Adenosine is the first-line drug used for termination of atrioventricular nodal reentry tachycardia (AVNRT). It is a potent purinergic blocker and generally blocks activation preferentially in the “slow pathway” of the AVNRT reentry circuit. In rare cases, the administration of adenosine may lead to atrial fibrillation or even asystole for a short period.
Adenosine administration should be given through a central, large bore intravenous (IV) needle, as it has a very short half-life. It should be followed by a saline flush and elevation of the extremity in which it is being injected. The initial dose is 6 mg followed by 12 mg and occasionally 18 mg. It should not be used in heart transplantation patients, it may be ineffective if given to a patient taking theophylline, and it may be potentiated by dipyridamole.
Verapamil
Intravenous verapamil 5-10 mg is effective to stop AVNRT and it may be better tolerated in some individuals than adenosine. Generally, adenosine is given as the initial therapy, but verapamil may be useful in patients who have recurrent episodes as there is a longer half-life. Intravenous verapamil may cause hypotension and bradycardia.
Diltiazem
Intravenous diltiazem can be effective to terminate AV nodal reentry supraventricular tachycardia but, in our experience, it is not recommended as the primary approach to stop AVNRT.
A 2017 emergency medicine review suggests that nondihydropyridine calcium channel blockers such as diltiazem and verapamil may be as effective as adenosine for converting narrow-complex tachycardia, particularly for refractory states, to sinus rhythm, and that no statistically significant difference exists in the conversion rate between these agents and adenosine (>90% conversion rate for both drug groups) (although adenosine is rapid acting). [3] However, adenosine is associated with more negative short-term side effects. Hemodynamically unstable patients should undergo electrical cardioversion. [3]
Intravenous beta-blockers
Intravenous metoprolol and esmolol parked potentially effective to terminate AVNRT particularly when it is sympathetically mediated but these are not generally used to treat AVNRT unless the other therapies are not available or there is reason to suspect that the patient has catecholamine mediated AVNRT and that it will recur early on. The dosing of metoprolol is 5-10 mg and the dosing of esmolol is 250-500 mcg/kg undiluted IV push.
Other acute therapies to stop AVNRT
Although there have been some recommendations to use IV amiodarone, propafenone, flecainide and other therapies, we do not recommend these therapies in patients who have known AVNRT, and we generally do not recommend these therapies for patients who have paroxysmal SVT that is suspected to be AVNRT.
Preventive therapy
Preventive therapy is needed for frequent, prolonged, or highly symptomatic episodes that do not terminate spontaneously or for those that cannot be easily terminated by the patient. Drugs that are used for prevention of recurrence include long-acting beta-blockers, calcium channel blockers, and digitalis alone or in combination. No comparative studies indicate that a calcium channel antagonist is preferable or superior to a beta-adrenergic blocker for long-term management.
Novel therapy
Etripamil is an investigational intranasal spray; 35-140 mg can convert 65-95% of SVT within 15 minutes compared to 35% of those receiving placebo. The safety and efficacy of this therapy based on the initial study suggests that self-administration of this therapy may be possible by patients but further real-life data may be necessary. [11, 12, 13] Such a therapy may be indicated in patients with frequent, recurrent, generally well-tolerated, SVT in patients who are not good candidates for ablation or who prefer not to undergo ablation. This therapy may also be useful in the acute setting in the hospital in lieu of intravenous adenosine. The advantages are that an intravenous line is not necessary and side effects are minimal.
Radiofrequency Catheter Ablation
Radiofrequency catheter ablation [10] of the reentrant circuit should be considered in patients who have frequent or highly symptomatic episodes, who do not want drug therapy, who cannot tolerate the drugs, or in whom drug therapy fails.
Radiofrequency catheter ablation is associated with cure rates of greater than 95%, with very low risk of atrioventricular (AV) block (< 1%) for patients with AV nodal reentry tachycardia (AVNRT). [10] This is an invasive procedure in which catheter electrodes are placed percutaneously via central veins into the heart. Tachycardia can be initiated by pacing and by programmed electrical stimulation delivered from the atria or the ventricles.
An ablation catheter electrode can be placed in the location of the slow AV nodal pathway, with radiofrequency energy delivered via the catheter to interrupt conduction via this pathway and thus eliminate the circuit.
Cryoablation
Cryoablation has been increasingly used for treating AVNRT, with reported safety and efficacy, [14] including in children. [15, 16] One review of the literature concluded that cryoablation is safe and effective for AVNRT and is an option in patients for whom the avoidance of AV block is a priority, such as children and young adults. [15] A more recent study also found cryoablation to be effective for 125 children with AVNRT (age >10 years), with comparable acute and mid-term follow-up success rates for both 6-mm and 8-mm tip catheters. [16]
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Atrioventricular Nodal Reentry Tachycardia. Electrophysiologic mechanism of atrioventricular nodal reentry tachycardia (AVNRT).
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Atrioventricular Nodal Reentry Tachycardia. Atypical atrioventricular nodal (AV) reentry tachycardia. Often, an inverted P wave is seen just before the QRS complex in leads II, III, aVF. This represents activation of the posterior septum due to antegrade conduction via the fast pathway and retrograde conduction via the slow pathway of the AV node.
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Atrioventricular Nodal Reentry Tachycardia. Typical atrioventricular nodal (AV) reentry tachycardia. In this electrocardiogram, the P wave appears immediately after or just within the QRS complex. Often a “pseudo R wave" is seen in lead V1 and a “pseudo S wave" in leads II, III, aVF. The retrograde P wave represents retrograde activation via the fast pathway, which is anterior septal and superior to the AV node.
Tables
Type of Tachycardia |
Treatment (Grade) |
Not Mentioned in 2019 Guidelines |
Narrow QRS tachycardias |
Verapamil and diltiazem; beta-blockers (now all are grade IIa) |
Amiodarone, digoxin |
Wide QRS tachycardias |
Procainamide, adenosine (both grade IIa); amiodarone (IIb) |
Sotalol, lidocaine |
Atrioventricular nodal re-entrant tachycardia (AVNRT) |
Acute: — |
Acute: amiodarone, sotalol, flecainide, propafenone |
Chronic: verapamil and diltiazem; beta-blockers (all IIa) |
Chronic: amiodarone, sotalol, flecainide, propafenone, “pill-in-the-pocket” approach |
|
Atrioventricular re-entrant tachycardia (AVRT) |
Beta-blockers (IIa); flecainide/propafenone (IIb) |
Amiodarone, sotalol, “pill-in-the-pocket” approach |
Adapted from Brugada J, Katritsis DG, Arbelo E, et al, for the ESC Scientific Document Group. 2019 ESC Guidelines for the management of patients with supraventricular tachycardia. The Task Force for the management of patients with supraventricular tachycardia of the European Society of Cardiology (ESC). Eur Heart J. 2019 Aug 31;ehz467. |
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