Atrioventricular Nodal Reentry Tachycardia

8 Interesting Facts of Atrioventricular Nodal Reentry Tachycardia 

1. Atrioventricular nodal reentry tachycardia is the most common type of paroxysmal supraventricular tachycardia; it is due to a reentry circuit in or around the atrioventricular node
2. Common symptoms include palpitations (often felt as neck pounding), chest pain, anxiety, dizziness, shortness of breath, polyuria, and lightheadedness
3. Diagnosis is based on history, physical examination, and ECG findings
4. Diagnosis often depends on ambulatory ECG monitoring (ie, Holter monitoring, event recorder, or loop recorder)
5. Management of acute tachycardia includes decreasing atrioventricular nodal conduction using vagal maneuvers and adenosine, proceeding to IV calcium channel blockers, β-blockers, and cardioversion or IV amiodarone if the tachycardia is not terminated
6. For unstable patients, treat with direct current synchronized cardioversion with 50 to 100 J
7. For minimally symptomatic patients with infrequent tachycardia, observation or pill-in-pocket episodic management is appropriate
8. For patients with frequent or more symptomatic episodes, catheter ablation, a procedure done under local anesthesia in cardiac catheterization laboratory, is usually curative

Pitfalls

• Most atrioventricular nodal reentry tachycardias are narrow complex tachycardias, with the QRS duration being less than 90 ms, but tachycardia-related bundle branch block may occur, causing a wide-complex tachycardia that may be confused with ventricular tachycardia
• Diagnostically exclude ventricular tachycardia and atrial fibrillation due to preexcitation before administering diltiazem or verapamil for presumed atrioventricular nodal reentry tachycardia, because hemodynamic instability or ventricular fibrillation may result

• Atrioventricular nodal reentry tachycardia is the most common type of paroxysmal supraventricular tachycardia; it is due to a reentry circuit (via a functionally and anatomically distinct pathway) in or around the atrioventricular node 
• Most common ECG pattern is a narrow QRS complex tachycardia without visible P waves (hidden within the QRS complex) and with a regular RR interval 

Classification 

• Typical (slow-fast)
  • Most common type of conduction in atrioventricular nodal reentry tachycardia
  • Atrial impulse proceeds antegrade down the slow pathway and then retrograde up the fast pathway
  • P wave occurs during (or just after) the QRS complex, with a short RP interval
• Atypical (slow-slow)
  • Uncommon
  • Atrial impulse proceeds antegrade and then retrograde via 2 distinct slow pathways
  • Slow-slow conduction results in the P wave occurring after the QRS complex, with a short RP interval
• Atypical (fast-slow)
  • Uncommon 
  • Atrial impulse proceeds antegrade down the fast pathway and then retrograde up the slow pathway
  • Fast-slow conduction results in the P wave occurring before the QRS complex, with a long RP interval

Clinical Presentation

History

• Patient may be asymptomatic if encountered during a normal sinus rhythm
• Typical symptoms include:
  • Sudden onset of palpitations/rapid heartbeat lasting seconds to hours; episodes usually resolve abruptly
  • Pulsation is often felt most in the carotid area, and it may be described as “pounding” or “shirt flapping” 
  • Dizziness or lightheadedness is common, but syncope occurs in only 15% of cases, typically at onset or during prolonged pause after abrupt termination of tachycardia 
  • Sudden onset of central chest pain
  • Shortness of breath
  • Anxiety
  • Polyuria due to release of atrial natriuretic peptide caused by increased atrial pressure from atrial contractions against a closed atrioventricular valve 
• Less commonly, chronic tachycardia has been present for a long time, and the patient presents with symptoms of heart failure due to cardiomyopathy
• Family history of arrhythmia in a first-degree relative may be noted

Physical examination

• Physical examination findings are usually normal, especially if symptoms have resolved by time of presentation
• When tachycardia is present:
  • Tachycardia is regular, with a rate of 140 to 250 beats per minute 
  • Hypotension may be present
  • Prominent jugular venous pulse with cannon waves will be seen
• Cardiovascular examination findings are usually otherwise normal, reflecting that this arrhythmia usually occurs in structurally normal hearts

Causes

• Reentry conduction circuit involving dual atrioventricular nodal pathways, most commonly in a patient without underlying heart disease
• Congenital heart disease sometimes results in this type of tachycardia 
  • Atrial septal defect
  • Tetralogy of Fallot
  • Ebstein anomaly of tricuspid valve
• Factors that can precipitate an episode include:
  • ­ Nicotine
  • ­ Excessive consumption of alcohol
  • ­ Recreational drugs (eg, psychostimulants; cocaine, amphetamines)
  • ­ Prescription drugs with sympathomimetic effects taken at usual doses (eg, decongestants, psychostimulant anorectics, β-agonists)
  • ­ Increased vagal tone

Risk factors and/or associations

Age

• Most commonly becomes symptomatic in adulthood; mean age of onset is 32 years 
• Accounts for 30% to 50% of supraventricular tachycardia cases in teenagers 
• Less common in younger children, but increases with age Accounts for 9% to 13% of supraventricular tachycardia cases in infants 
  • Most supraventricular tachycardia cases in infants are caused by an accessory pathway rather than a reentry circuit

Sex

• More common in females 

Other risk factors/associations

• Risk factors for supraventricular tachycardia in general include:
  • History of cardiovascular disease
  • Previous myocardial infarction
  • Mitral valve prolapse
  • Rheumatic heart disease
  • Pericarditis
  • Pneumonia
  • Chronic lung disease
  • ­ Hyperthyroidism
  • Digoxin toxicity

Diagnostic Procedures

Primary diagnostic tools

• Diagnosis is based on history, physical examination, and ECG findings 
• For patients who are asymptomatic at time of evaluation, ambulatory ECG monitoring is recommended (ie, 24-hour Holter monitoring, or extended loop recorder) 
• Laboratory testing is not routine for most patients, but thyroid testing may uncover unrecognized hyperthyroidism as an underlying cause 
• Diagnostic imaging is not routine for patients with the paroxysmal variant, but in patients with sustained (nonparoxysmal) tachycardia, obtain echocardiographic imaging to evaluate for structural abnormalities 
• Electrophysiologic study is indicated to confirm the mechanism of tachycardia in patients who will be treated with catheter ablation 

Laboratory 

• Thyroid function tests to diagnose hyperthyroidism should include TSH level and free thyroxine level
  • Low or undetectable TSH level combined with elevated free thyroxine level is consistent with hyperthyroidism

Imaging

• Chest radiography
  • Indicated only for patients with symptoms or signs suggestive of congestive heart failure or pulmonary disease 
• Transthoracic echocardiography
  • Indicated for patients with documented, sustained (nonparoxysmal) supraventricular tachycardia to evaluate for structural heart defects that cannot be determined by physical examination or ECG 

Functional testing

• ECG
  • QRS complexes at rates of 140 to 250 beats per minute with a regular rhythm and of supraventricular origin 
  • In typical (slow-fast) variant
    • RP interval is shorter than PR interval; P waves are usually not seen because they are buried in QRS complex 
    • Alternatively, P wave may be seen as a small terminal P wave that is not present during sinus rhythm 
      • Appears as slight positive deflection at end of QRS complex in V₁ (pseudo–R prime wave) 
      • Appears as slight negative deflection at end of QRS complex in inferior leads (pseudo–S wave) 
  • In atypical (slow-slow) variant
    • P wave is inscribed after QRS complex 
  • In atypical (fast-slow) variant
    • RP interval is longer than PR interval; retrograde P wave is visible before QRS complex (long RP variant) 
    • P waves are negative in leads II, III, aVF, and V₆ but are positive in V₁ 
  • Most atrioventricular nodal reentry tachycardias are narrow complex tachycardias, with QRS duration of less than 120 ms, unless there is aberrant conduction 
    • If aberrant conduction exists, it is more commonly a right bundle branch block pattern 

Procedures

• Procedure is performed under conscious sedation via femoral venous access
• Quadripolar electrode catheters are placed at high right atrium, right ventricular apex or base, and His bundle region, and decapolar catheter is placed at coronary sinus
• Confirms diagnosis before catheter ablation treatment
• Systemic infection/sepsis
• Acute coronary syndrome
• Heart failure unrelated to arrhythmia
• Major bleeding tendencies
• Deep vein thrombosis, if femoral vein cannulation is needed
• Findings include dual-node physiology, a discontinuous pattern of atrial to ventricular conduction reflecting the differing conduction properties of the fast and slow conduction channels

Other diagnostic tools

• Ambulatory ECG monitoring
  • Diagnostic yield correlates with the duration of monitoring and depends on the accuracy of patient reporting of symptoms 
    • Holter method
      • Ambulatory 24- to 48-hour Holter recording is used to capture evidence of frequent but transient tachycardias
      • Portable device is attached to patient with ECG wires and electrodes
      • Continuous ECG tracing is made
      • Best for patients who experience symptoms every day 
    • Event recorder or loop recorder (external or implantable) 
      • 2 weeks of ECG monitoring may provide best diagnostic yield 
      • Event recorders
        • Indicated in patients with less frequent arrhythmias as an alternative to 24-hour Holter monitoring
        • Patient wears device (usually on wrist) and activates device (pushes button) to record when symptomatic
        • Will not record event if patient delays activating the device
      • External loop recorders
        • Similar to event recorders; worn on the chest
        • Has a continuous looping memory recording; can retrieve recording of ECG even if patient does not activate the device until several minutes after a symptomatic event
    • Implantable loop recorders
      • Requires minor surgical procedure
      • Recommended only in patients with symptoms of less than 2 episodes per month and with severe hemodynamic instability

Differential Diagnosis

Most common

• Differential diagnosis of narrow QRS complex tachycardia
  • Atrioventricular reentry tachycardia
    • An anatomically defined circuit that consists of 2 distinct pathways; most commonly the antegrade conduction is via the atrioventricular node and the retrograde conduction is via an accessory pathway (orthodromic conduction), but the reverse (antidromic conduction) may also occur
    • Patients tend to present at a much younger age compared with those with atrioventricular nodal reentry tachycardia
    • Differentiating atrioventricular reentry tachycardia from atrioventricular nodal reentry tachycardia is important for the cardiologist but less important for urgent treatment in the emergency department, as treatment is the same
    • Diagnostic effort is aided by full 12-lead ECG and rhythm strip
      • Orthodromic conduction
        • Narrow QRS complexes are seen unless aberrancy is present, in which case the QRS resembles that seen with bundle branch block; retrograde P waves are seen
        • Retrograde P wave is seen in ST-T wave
        • Retrograde P is negative in leads I and aVL if it conducts over a left lateral accessory pathway
        • Retrograde P is negative in leads II, III, and aVF if it conducts over a septal or posteroseptal accessory pathway
      • Antidromic conduction
        • QRS complexes are wide and resemble those seen with ventricular tachycardia; rhythm may be irregular
        • RP interval is short
  • Atrial tachycardia (focal)
    • Regular atrial rhythm having a constant rate of 100 beats per minute or greater
    • Most commonly seen with structural cardiac disease
    • Usually paroxysmal rather than incessant; patient may be dyspneic or have chest pressure
    • Diagnostic effort is aided by full 12-lead ECG and rhythm strip
      • P wave morphology and axis are typically abnormal, as impulse originates outside sinus node (waves may be normal if impulse originates very close to sinus node)
      • Presence of a positive or biphasic P wave in lead aVL indicates a right atrial focus, and a positive P wave in lead V₁ indicates a left atrial focus
      • AV conduction may be 1:1, 2:1, or higher, depending on atrial rate (atrial tachycardia with block)
  • Multifocal atrial tachycardia 
    • More common in patients older than 50 years
    • Hypoxia is usually a trigger (usually associated with heart failure, pulmonary disease, pulmonary embolism, and pneumonia)
    • Atrial rates are typically 100 to 130 beats per minute
    • Diagnostic effort is aided by full 12-lead ECG and rhythm strip
      • P waves have at least 3 distinct wave morphologies
      • Each QRS complex is preceded by a P wave, but irregular PR and PP intervals occur (may be mistaken for atrial fibrillation)
      • An isoelectric baseline occurs between the P waves
  • Atrial fibrillation
    • Irregular rhythm of unclear electrical mechanism; most common in older adults with heart disease or hypertension
    • Many patients are asymptomatic or may present with nonspecific symptoms such as fatigue or exercise intolerance
    • Other symptoms include palpitation, dyspnea, chest pain, or dizziness
    • Diagnostic effort is aided by full 12-lead ECG and rhythm strip showing absence of P waves and showing fibrillary waves at the isoelectric baseline having different morphology, amplitude, and intervals
  • Atrial flutter
    • 2:1 atrioventricular conduction that results in a classically defined rate of 150 beats per minute
    • Presents with increased heart rate, irregular pulse, and palpitation
    • Diagnostic effort is aided by full 12-lead ECG and rhythm strip
      • Unlike in atrial fibrillation, ECG shows coordinated electrical activity in the atria
      • ECG shows sawtooth pattern of the F (flutter) waves, especially in leads II, III, aVF, or V₁
      • F waves may not be clearly identified with rapid 1:1 atrioventricular conduction
  • Wolff-Parkinson-White syndrome
    • Congenital condition involving abnormal electrical conduction via an accessory pathway between the atria and the ventricles, which causes ventricular preexcitation
    • Diagnostic effort is aided by full 12-lead ECG and rhythm strip; during normal sinus rhythm, these show a short PR interval and a widened QRS with an initial delta wave
    • Wolff-Parkinson-White syndrome results in a predisposition to atrioventricular reentry tachycardia, atrial fibrillation, and atrial flutter
• Differential diagnosis of atrioventricular nodal reentry tachycardia in the presence of a bundle branch block (presents as wide QRS complex tachycardia)
  • Ventricular tachycardia
    • A series of 3 or more ventricular complexes, occurring at a rate of 100 to 250 beats per minute, is the most frequently encountered life-threatening arrhythmia and the most common type of wide-complex tachycardia in a patient with a previous myocardial infarction
    • Often difficult to differentiate from atrioventricular nodal reentry tachycardias with a right or left bundle branch block
      • Wide-complex tachycardia with a typical right bundle branch block morphology appearance on 12-lead ECG is more suggestive of supraventricular tachycardia with aberrancy than when a left bundle branch block pattern is present
      • RS interval (from the initial R to the nadir of S) longer than 100 ms in any precordial lead is highly suggestive of ventricular tachycardia
      • QRS pattern with negative concordance in the precordial leads is diagnostic for ventricular tachycardia
    • Definitive diagnosis may require electrophysiologic study

Treatment Goals 

• Control tachyarrhythmia
• Prevent recurrence
• Prevent acute and long-term complications

Admission criteria 

Patients with hemodynamic instability, chest pain, or persistent atrioventricular nodal reentry tachycardia (unresponsive to vagal maneuvers and/or pharmacotherapy)

Patients with frequent or prolonged episodes unresponsive to medical therapy during outpatient treatment (admit and monitor for medication management)

Criteria for ICU admission 

• Patients with ongoing hemodynamic instability
• Patients with significant cardiopulmonary comorbidities

Recommendations for specialist referral 

• Consult cardiologist for:
  • Uncertain diagnosis
  • Wide-complex tachycardia
  • Evaluation of severe symptoms (eg, dyspnea, syncope) that arise during palpitations
  • Consideration of long-term therapy
  • Failure of medical therapy
  • Consideration of ablative therapy for patients who wish to avoid lifelong medical therapy

Treatment Options

Acute management

• For unstable patients (eg, those with hypotension, altered mental status, ongoing chest pain, pulmonary edema): 
  • Perform direct current synchronized cardioversion using 50 to 100 J
  • In most cases, a combination of rapid-acting sedative and analgesic should be administered via IV to conscious patients before cardioversion (eg, propofol, fentanyl, midazolam, etomidate)
• For stable patients 
  • Vagal maneuver(s) (ie, Valsalva maneuver, coughing, application of cold to face, carotid artery massage) to terminate the arrhythmia are first line therapy for most patients 
    • Increased neurologic risks for patient with carotid artery massage; another method is preferable for many patients 
    • If carotid artery massage is elected, confirm that there is no carotid artery bruit before attempting; contraindicated if bruit is present and in patients with known carotid artery disease or recent stroke or transient ischemic attack 
    • Make ECG recording during all treatments, including vagal maneuvers and IV drug administration
  • If vagal maneuvers are unsuccessful or contraindicated:
    • Rapid IV bolus of adenosine is first line therapy owing to its rapid onset and short half-life (10 seconds)
      • Monitor ECG during treatment
        • Will quickly terminate atrioventricular nodal reentry tachycardia in approximately 95% of patients 
        • Will unmask atrial activity in other arrhythmias (eg, atrial flutter, atrial tachycardia)
      • Transient atrial fibrillation may occur (uncommon)
      • Vagal maneuvers may be repeated after administration if necessary
      • Use with caution in patients with:
        • Autonomic neuropathy
        • Pericarditis or pericardial effusion
        • Stenotic valvular heart disease
        • Stenotic carotid artery disease with cerebrovascular insufficiency
        • Uncorrected hypovolemia
    • IV calcium channel blockers (verapamil or diltiazem) are second line therapy when adenosine is contraindicated or ineffective or there is rapid recurrence of tachyarrhythmia 
    • IV β-blockers are also effective as second line therapy 
    • If IV calcium channel blockers or β-blockers do not terminate the tachycardia (or are contraindicated), proceed to one of the following options: 
      • Perform direct current synchronized cardioversion using 50 to 100 J (will be ineffective for rhythms that break or recur spontaneously) 
      • Give IV amiodarone 
    • A short-acting intranasal calcium channel blocker, etripamil, is emerging as an effective treatment for terminating supraventricular tachycardias; currently still experimental 

Long-term management

• For patients who remain asymptomatic or have infrequent, minimally symptomatic episodes of tachycardia, there are 2 treatment approaches, as follows: 
  • Clinical follow-up without treatment is preferred (nearly half may improve over time and become asymptomatic) 
    • Instruct patient on performance of vagal maneuvers to terminate any future episodes on their own; advise patient to seek medical attention if the arrhythmia persists despite several attempts at self-performed vagal maneuvers
  • Pill-in-pocket management
    • Selected patients may be prescribed single-dose therapy with drug (or drug combination) to keep on hand and use during an episode of tachycardia 
    • Indicated for patients with infrequent, hemodynamically stable, well-tolerated tachycardia that is prolonged (lasts hours)
    • Avoid in patients with left ventricular dysfunction, preexcitation syndromes, or sinus bradycardia
    • Use immediate-release formulations
    • Oral therapy with 1 dose of diltiazem (120 mg) plus 1 dose of propranolol (80 mg) has been reported to be superior to placebo and single-dose flecainide; higher propranolol dose (160 mg) is also commonly used
    • Complications may include hypotension and bradycardia
• For patients who have frequent episodes of tachycardia, or infrequent episodes that are more than mildly symptomatic: 
  • First line therapy is radiofrequency catheter ablation of the slow conduction track 
    • Superior to antiarrhythmic drug therapy; long-term success rate is better than 95% 
    • Overall low rate of complications; complete heart block requiring pacemaker implantation is main serious complication, occurring in less than 1.0% of patients 
  • If patient does not prefer ablation, daily prophylaxis with an atrioventricular nodal blocking agent is recommended (ie, diltiazem, verapamil, or a β-blocker; avoid in patients with systolic heart failure) 
  • If atrioventricular nodal blocking agent is not effective 
    • Reconsider ablation 
    • Add flecainide or propafenone
      • Contraindicated for patients with structural heart disease
    • Consider amiodarone, digoxin, dofetilide, or sotalol in consultation with a cardiologist 

Drug therapy

• For management of acute episode unresponsive to vagal maneuvers (or when vagal maneuvers are contraindicated):
  • Antiarrhythmic agent
    • Adenosine
      • Adenosine Solution for injection [Cardioversion]; Infants, Children, and Adolescents weighing less than 50 kg: 0.1 mg/kg rapid IV/IO bolus followed immediately by a saline flush. If conversion does not occur within 1 to 2 minutes, give an additional 0.2 mg/kg rapid IV/IO bolus followed by a saline flush.
      • Adenosine Solution for injection [Cardioversion]; Children and Adolescents weighing 50 kg or more: 6 mg rapid IV/IO bolus followed immediately by a saline flush. If conversion does not occur within 1 to 2 minutes, give an additional 12 mg rapid IV/IO push followed by a saline flush.
      • Adenosine Solution for injection [Cardioversion]; Adults: 6 mg rapid IV/IO bolus followed immediately by a saline flush. If conversion does not occur within 1 to 2 minutes, give an additional 12 mg rapid IV/IO push followed by a saline flush.
  • Calcium channel blocker
    • Verapamil
      • Verapamil Hydrochloride Solution for injection; Children and Adolescents: Initially, 0.1 to 0.3 mg/kg (i.e., 2 to 5 mg) IV bolus, given over at least 2 minutes. Max single dose: 5 mg. If no response, repeat dose in 30 minutes. Max total dose: 10 mg.
      • Verapamil Hydrochloride Solution for injection; Adults: Initially, 5 to 10 mg (0.075 to 0.15 mg/kg) IV over at least 2 minutes. If no adequate response after 30 minutes, may give an additional 10 mg (0.15 mg/kg). An optimal interval for subsequent doses has not been determined and should be individualized for each patient. Clinical guidelines recommend 2.5 to 5 mg IV over 2 minutes. If no therapeutic response or adverse reaction is seen, may administer repeated doses of 5 to 10 mg every 15 to 30 minutes up to a total dose of 20 mg. Alternative dosing is 5 mg IV every 15 minutes, up to a total dose of 30 mg.
    • Diltiazem
      • Diltiazem Hydrochloride Solution for injection; Infants older than 7 months†, Children†, and Adolescents†: 0.25 mg/kg IV bolus over 5 minutes followed by 0.05 to 0.15 mg/kg/hour continuous IV infusion (mean 0.11 mg/kg/hour) has been reported.
      • Diltiazem Hydrochloride Solution for injection; Adults: 0.25 mg/kg IV bolus over 2 minutes. After 15 minutes, 0.35 mg/kg IV over 2 minutes may be given. Individualize as needed. Begin 10 mg/hour continuous IV infusion immediately after IV bolus. Some patients respond to lower doses (e.g., 5 mg/hour). Max: 15 mg/hour.
  • β-blocker
    • Esmolol
      • Esmolol Hydrochloride Solution for injection; Infants†, Children†, and Adolescents†: 100 to 500 mcg/kg IV, then 50 to 500 mcg/kg/minute continuous IV infusion.
      • Esmolol Hydrochloride Solution for injection; Adults: 50 mcg/kg/minute continuous IV infusion, initially. Titrate by 50 mcg/kg/minute every 4 minutes until goal heart rate is attained. Usual dose: 25 to 200 mcg/kg/minute. Max: 300 mcg/kg/minute. May give 500 mcg/kg IV over 1 minute at initiation and before each infusion rate increase up to 3 doses.
    • Propranolol
      • Propranolol Hydrochloride Solution for injection; Children† and Adolescents†: 0.01 mg/kg/dose IV push over 10 minutes, repeat every 6 to 8 hours as needed. May titrate dosage gradually as needed. Max: 0.15 mg/kg/dose or 3 mg/dose.
      • Propranolol Hydrochloride Solution for injection; Adults: 1 to 3 mg IV at a rate no faster than 1 mg/minute; repeat if necessary in 2 minutes. Separate subsequent doses by at least 4 hours. Guidelines recommend 0.5 to 1 mg IV over 1 minute; repeat if necessary up to total dose of 0.1 mg/kg. In geriatric patients, use conservative initial doses and titrate carefully.
• For management of acute episode unresponsive to vagal maneuvers, adenosine, calcium channel blockers, or β-blockers:
  • Antiarrhythmic agent
    • Amiodarone
      • Amiodarone Hydrochloride Solution for injection; Adults: 150 mg IV over 10 minutes, followed by 1 mg/minute continuous IV infusion for 6 hours then 0.5 mg/minute continuous IV infusion for 18 hours. After 24 hours, change to PO or consider decreasing rate to 0.25 mg/minute.
• For long-term management
  • Pill-in-pocket single-dose management of acute (paroxysmal) episodes
    • Diltiazem (120 mg immediate release) by mouth plus propranolol (80-160 mg) by mouth
      • Diltiazem Hydrochloride Oral tablet; Adults: 120 mg PO as a one-time dose given with propranolol. 
      • Propranolol Hydrochloride Oral tablet; Adults: 80 to 160 mg PO as a one-time dose given with diltiazem. 
  • Daily prophylaxis
    • Atrioventricular nodal blocking agent
      • Diltiazem
        • Diltiazem Hydrochloride Oral tablet, extended-release; Adults: 120 to 360 mg PO once daily.
      • Verapamil
        • Verapamil Hydrochloride Oral tablet; Children† and Adolescents†: Limited data available; 2 to 7 mg/kg/day PO (Max: 480 mg/day) divided 3 times daily has been suggested.
        • Verapamil Hydrochloride Oral tablet; Adults: 240 to 480 mg/day PO, given in 3 to 4 divided doses.
      • Propranolol
        • Propranolol Hydrochloride Oral tablet; Neonates†, Infants†, Children†, and Adolescents†: Initially, 0.5 to 1 mg/kg/day PO, divided every 6 to 8 hours. Titrate by 1 mg/kg/day every 3 to 5 days as needed. Usual maintenance is 2 to 4 mg/kg/day PO. Max: 16 mg/kg/day or 60 mg/day. In older adolescents, 10 to 30 mg/dose PO every 6 to 8 hours may be given.
        • Propranolol Hydrochloride Oral tablet; Adults: Initially, 10 to 30 mg PO 3 or 4 times daily. Dosage may be increased up to 160 to 320 mg/day PO, given in 3 to 4 divided doses. In geriatric patients, use conservative initial doses and titrate carefully.
    • Antiarrhythmic agent
      • Flecainide
        • Flecainide Acetate Oral tablet; Infants 1 to 6 months: Initially, 50 mg/m2/day PO given in 2 to 3 divided doses; increase as needed every 4 days to achieve clinical goals (Max: 200 mg/m2/day PO). Alternatively, 1 to 6 mg/kg/day PO given in 2 to 3 divided doses (Max: 8 mg/kg/day PO) has been recommended.
        • Flecainide Acetate Oral tablet; Infants, Children, and Adolescents 7 months to 17 years: Initially, 100 mg/m2/day PO given in 2 to 3 divided doses; increase as needed every 4 days to achieve clinical goals (Max: 200 mg/m2/day PO). Alternatively, 1 to 6 mg/kg/day PO given in 2 to 3 divided doses (Max: 8 mg/kg/day PO) has been recommended.
        • Flecainide Acetate Oral tablet; Adults: Initially, 50 mg PO every 12 hours. Increase dose by increments of 50 mg PO twice daily every 4 days as needed. Max: 300 mg/day.
      • Propafenone
        • Propafenone Hydrochloride Oral tablet; Infants†: Initially, 100 to 200 mg/m2/day PO, in 3 divided doses for 3 days or more; dose may be increased by 100 mg/m2/day every 3 days, if needed, up to 600 mg/m2/day PO, given in 3 divided doses. Average dose: 300 to 500 mg/m2/day.
        • Propafenone Hydrochloride Oral tablet; Children†: Initially, 8 to 10 mg/kg/day PO in 3 divided doses. Increase by 2 to 3 mg/kg/day every 2 to 3 days PRN, up to 15 mg/kg/day PO (or 600 mg/m2/day PO), given in 3 divided doses. Average dosage: 13 to 16 mg/kg/day.
        • Propafenone Hydrochloride Oral tablet; Adults: Very limited data. 300 mg PO every 8 hours for 48 hours has been used.

Nondrug and supportive care

Advise lifestyle modifications, as follows:

• Avoid caffeinated beverages and tobacco 
• Avoid stimulant drugs (prescription or recreational) 
• Abstain from alcohol 
• Get adequate sleep

Procedures

Valsalva maneuver 

General explanation

• Place patient in supine position
• Patient performs this maneuver by holding breath and bearing down against a closed glottis for 10 to 30 seconds 
• Mouth is kept closed and nose is kept pinched shut while patient tries to breath out
• Maneuver greatly increases pressure inside chest cavity, which stimulates vagus nerve and increases vagal tone

Indication

• Terminate an episode of atrioventricular nodal reentry tachycardia

Contraindications

• Retinopathy
• Dyspnea causing inability to hold breath
• Unclipped cerebral aneurysm

Complications

• May worsen preexisting retinopathy due to capillary hemorrhages
• May cause sudden loss of central vision or scotoma (Valsalva retinopathy), which usually spontaneously resolves as hemorrhages resorb

Application of cold to the face 

General explanation

• For infants and young children in whom cooperation is an issue, may cool face using an ice pack or a cold, wet towel; take care not to occlude the airway
• Apply to forehead and bridge of nose for up to 30 seconds

Indication

• Terminate an episode of atrioventricular nodal reentry tachycardia

Carotid sinus massage 

General explanation

• Confirm absence of bruit by auscultation (procedure still poses greater neurologic risk than other vagal maneuvers) 
• Perform in supine position
• Apply steady pressure over either right or left carotid artery gently for 5 to 10 seconds at level of thyroid cartilage 
• Simultaneously, monitor heart rhythm and blood pressure
• Effective in terminating atrioventricular nodal reentry tachycardia

Indication

• Terminate an episode of atrioventricular nodal reentry tachycardia

Contraindications

• Carotid artery disease (known or suspected by presence of bruit)
• Stroke or transient ischemic attack within 3 months
• Acute myocardial infarction
• Digoxin toxicity (known or suspected)

Complications

• Rare
  • Neurologic complications due to carotid embolization or occlusion 
  • Asystole, ventricular tachycardia, or ventricular fibrillation

Radiofrequency catheter ablation 

General explanation

• Procedure is done under local anesthesia in cardiac catheterization laboratory
• Ablation of the slow pathway is the most common approach
• Definitive cure for atrioventricular nodal reentry tachycardia

Indication

• First line therapy in patients with hemodynamically poorly tolerated or frequent episodes
• Failure of medical therapy
• Patients unwilling to continue medication for extended period of time

Contraindications

• Sepsis
• Deep venous thrombosis if femoral vein is cannulated
• Angina and heart failure unrelated to arrhythmia

Complications

• Bleeding or infection at site of catheter insertion
• Thromboembolism
• Damage to endothelium from catheter movements
• New arrhythmia patterns/heart block
• Puncture of vessels or myocardium

Direct current cardioversion 

General explanation

• Cardioversion is rarely necessary for patients with atrioventricular nodal reentry tachycardia
• Using 50 to 100 J can terminate the tachyarrhythmia
• Most effective method for restoring sinus rhythm

Indication

• When the tachycardia is refractory to other medical therapies or the tachycardia is causing hemodynamic instability (eg, lightheadedness or hypotension, altered mental status, chest pain, pulmonary edema)

Contraindications

• Sinus tachycardia
• Digoxin toxicity
• Junctional or multifocal atrial tachycardia

Complications

• Thromboembolism
• New arrhythmia patterns/heart block

Special populations

• Pediatric population
  • Atrioventricular nodal reentry tachycardia is rare in children and becomes more frequent in adolescents
  • Children rarely experience severe symptoms during episodes
  • Recurrent episodes or episodes with hemodynamic instability may require chronic medication therapy, or ablation may be recommended
  • After the first episode of atrioventricular nodal reentry tachycardia, manage most children with observation only, without chronic medical therapy unless there are recurrent episodes
• Pregnant patients 
  • Can use direct current cardioversion safely during all phases of pregnancy
  • Catheter ablation is recommended treatment in patients with illness refractory to drug therapies and poorly controlled supraventricular tachycardia 
  • Avoid β-blockers in pregnancy
    • Intrauterine growth restriction and premature birth have been reported with atenolol, especially when it is used in first trimester

Monitoring

• Monitor patients receiving daily prophylactic oral antiarrhythmic medication
  • Amiodarone
    • In long-term use, monitor CBC, liver function test results, and thyroid hormone levels
  • Flecainide
    • Monitor serum or plasma level of flecainide; toxicity is frequent with serum levels greater than 1000 ng/mL
    • Monitor serum creatinine and BUN levels
  • Propafenone
    • In long-term use, monitor serum creatinine and BUN levels

Complications

• Myocardial infarction
  • Most common in patients with underlying coronary artery disease
• Tachycardia-mediated cardiomyopathy
  • Occurs if tachycardia persists for longer duration (weeks to months)
• Congestive heart failure
  • Patients with tachycardia-induced cardiomyopathy can develop congestive heart failure

Prognosis

• Usually well tolerated and non–life-threatening 
• In the absence of structural heart disease, prognosis is good
• Patients with structural heart disease, congenital heart disease, or lung disease are less likely to tolerate atrioventricular nodal reentry tachycardia and less likely to experience treatment response

Prevention 

• Advise as follows:
  • Stop smoking
  • Abstain from alcohol
  • Manage hypertension
  • Maintain healthy diet and regular exercise
  • Try to lose weight if obese
  • Consider medical therapy to reduce risk of recurrences

References

Kotadia ID et al: Supraventricular tachycardia: an overview of diagnosis and management. Clin Med (Lond). 20(1):43-7, 2020