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Supraventricular Tachycardia, Emergency Medicine

Basics

Description

- Wide complex SVT: - Conduction is outside of the normal His-Purkinje system. - Accessory pathway or a bundle branch block is present. - More common in younger patients without structural disease - Always suspect a ventricular rhythm with a wide complex rhythm - Treat as ventricular tachycardia (VT) unless absolutely certain of SVT

- Atrial tachycardia: - Precipitated by a premature atrial or ventricular contraction - Electrolyte disturbances - Drug toxicity (i.e., theophylline) - Hypoxia - Increased atrial pressure

- Junctional tachycardia: - AV nodal re-entry - Myocardial ischemia - Structural heart disease - Pre-excitation syndromes

- Vital signs: - Tachycardia - BP normal or hypotensive - Respiratory rate normal or tachypneic

- CXR: - Assess cardiac size - Evaluate for pulmonary process - More useful in AF/flutter

- Atrial flutter: - Regular atrial rate usually >300 - Beat-to-beat uniformity of cycle length, polarity, and amplitude - Sawtooth flutter waves directed superiorly and most visible in leads II, III, aVF - AV block, usually 2:1, but occasionally greater or irregular

- Junctional tachycardia: - Usually 1:1 conduction, with ventricular rates equaling the atrial rate. - May be either paroxysmal or sustained - Ventricular rates >200 bpm in an adult suggest an accessory pathway syndrome such as WPW syndrome. - Absence of preceding P-waves - Often retrograde P-waves buried in the QRS

- Wide complex SVT: - Try to determine whether VT or SVT with aberrancy - If in doubt must be treated as VT - Brugada criteria may help identify VT (See "Ventricular Tachycardia " ). - Verapamil is absolutely contraindicated. - Adenosine should be reserved for SVT with aberrancy and is rarely indicated. - Electrical cardioversion: - Fewer potential complications than antiarrhythmic drugs when mechanism unknown

  • Rhythm that originates ectopically above the His bundle
  • Heart rate of 100 bpm or greater
  • Irregular narrow complex supraventricular tachycardia (SVT):Atrial fibrillation (AF):Most common form of pathologic SVT seen in the ED10% of people >75 yr of age have AF.Atrial flutter with variable blockMultifocal atrial tachycardia
  • Regular narrow complex SVT:Atrial flutterAtrioventricular nodal re-entry tachycardia (AVNRT):60% of SVT in adults, 70% are femaleTypically present age 30 " 40 yrAtrioventricular reciprocating tachycardia (AVRT) involving an accessory pathway
  • Wide complex SVT:Conduction is outside of the normal His-Purkinje system.Accessory pathway or a bundle branch block is present.More common in younger patients without structural diseaseAlways suspect a ventricular rhythm with a wide complex rhythmTreat as ventricular tachycardia (VT) unless absolutely certain of SVT

Etiology

  • Atrial tachycardia:Precipitated by a premature atrial or ventricular contractionElectrolyte disturbancesDrug toxicity (i.e., theophylline)HypoxiaIncreased atrial pressure
  • Junctional tachycardia:AV nodal re-entryMyocardial ischemiaStructural heart diseasePre-excitation syndromes
  • Wolff " Parkinson " White (WPW) syndrome:Intrinsic accessory pathwayDrug and alcohol toxicity
  • AF:HTNCoronary artery diseaseHypo-/hyperthyroidismHeavy alcohol intakeMitral valve diseaseChronic pulmonary diseasePulmonary embolusWPW syndromeHypoxiaDigoxin toxicityChronic pericarditisSepsis
  • Atrial flutter:Ischemic heart diseaseValvular heart diseasesCHFMyocarditisCardiomyopathiesPulmonary embolusOther pulmonary disease

Diagnosis

Signs and Symptoms

  • Palpitations (most common)
  • Lightheadedness, pressure in the head
  • Dyspnea
  • Diaphoresis
  • Dizziness
  • Weakness
  • Chest discomfort
  • Syncope
  • Prominent neck veins "frog sign "
  • Signs of instability:Mental status changesChest pain/ischemiaAcute pulmonary edemaHypotension

History

  • Abrupt onset of palpitations, lightheadedness, weakness, chest pain:Current symptomsPrevious episodes
  • Insidious onset of generalized weakness, exercise intolerance, and malaise
  • Prior cardiac history
  • Medications:Over-the-counter, decongestants
  • Illicit drug use

Physical Exam

  • Vital signs:TachycardiaBP normal or hypotensiveRespiratory rate normal or tachypneic
  • Cardiac:Regular or irregularly irregular rhythmJVD may be present in setting of heart failure
  • Pulmonary:Rales may be present in setting of heart failure.

Essential Workup

  • ABCs, assess stable vs. unstable
  • History
  • EKG

Diagnosis Tests & Interpretation

Lab

  • CBC
  • Electrolytes
  • Cardiac enzymes, BNP
  • Thyroid function (usually low yield)

Imaging

  • CXR:Assess cardiac sizeEvaluate for pulmonary processMore useful in AF/flutter

Diagnostic Procedures/Surgery

  • EKG:AF:Atrial fibrillatory waves without discernable P-wavesIrregularly irregular ventricular rate of 100 " 220Atrial flutter:Regular atrial rate usually >300Beat-to-beat uniformity of cycle length, polarity, and amplitudeSawtooth flutter waves directed superiorly and most visible in leads II, III, aVFAV block, usually 2:1, but occasionally greater or irregularMultifocal atrial tachycardia:3 distinctly different P-waves with varying pulse rate intervalsAtrial tachycardia:Rate of 100 " 200 bpmP-wave precedes QRS and is morphologically different from the sinus P-wave.Junctional tachycardia:Usually 1:1 conduction, with ventricular rates equaling the atrial rate.May be either paroxysmal or sustainedVentricular rates >200 bpm in an adult suggest an accessory pathway syndrome such as WPW syndrome.Absence of preceding P-wavesOften retrograde P-waves buried in the QRS

Differential Diagnosis

  • Sinus tachycardia:SepsisHypovolemiaPericardial tamponadeAcute MIDrug intoxication
  • Wide complex tachycardias:Distinguish between supraventricular with aberrancy or ventricular origins.

Treatment

Pre-Hospital

  • Supplemental oxygen
  • IV access
  • Monitor

Initial Stabilization/Therapy

Ed Treatment/Procedures

  • AF/atrial flutter:AF is most likely diagnosed when the rhythm is irregularWhen unstable, then immediate synchronized cardioversionWhen stable, rate control is a priority: ²-blockers or calcium channel blockers, amiodarone, and digoxinCardioversion in stable patients should not be attempted unless the dysrhythmia is known to be acute (<48 hr in duration) due to risk of embolism
  • WPW syndrome:Consider direct current cardioversion or amiodarone, flecainide, or procainamide.Avoid AV node blocking agents such as adenosine, ²-blockers, calcium channel blockers, and digoxin.
  • In regular narrow complex SVTs:Vagal maneuvers will occasionally terminate the dysrhythmia:Carotid massage (although beware of carotid disease, especially in elderly)Ice to face in children (mammalian diving reflex)Valsalva maneuverIf this is unsuccessful, adenosine is the drug of choice.Adenosine 6 mg will convert 60 " 80% of SVT
  • Wide complex SVT:Try to determine whether VT or SVT with aberrancyIf in doubt must be treated as VTBrugada criteria may help identify VT (See "Ventricular Tachycardia " ).Verapamil is absolutely contraindicated.Adenosine should be reserved for SVT with aberrancy and is rarely indicated.Electrical cardioversion:Fewer potential complications than antiarrhythmic drugs when mechanism unknownAntidysrhythmic drugs:IV procainamide and IV amiodaroneLidocaine is less effective, although sometimes more readily available.Bretylium lacks any evidence of efficacy.
  • Synchronized cardioversion for unstable patient 0.5 " 1 J/kg
  • SVT is the most common dysrhythmia seen in young adults and children without underlying heart disease:Initial vagal maneuvers:Infants: Ice/water bag to forehead 15 secChildren: Valsalva: "Blow into straw "
  • Aberrant conduction:WPW syndrome and AVNRT are the 2 most common forms of SVT seen in children.
  • Use verapamil only >1 yr of age.
  • Adenosine considered safe
  • 2nd-line agents IV propranolol or metoprolol
  • Avoid verapamil (maternal hypotension)
  • Cardioversion is safe.

Medication

  • Adenosine: 6 mg (peds: 0.1 mg/kg up to 6 mg) rapid IVP; if no response after 1 " 2 min, then 12 mg (peds: 0.2 mg/kg up to 12 mg), may repeat 12 mg (0.2 mg/kg)
  • Amiodarone: Load with 15 mg/min IV over 10 min (peds: 5 mg/kg over 20 " 60 min), then 1 mg/min IV for 6 hr, then 1 mg/min IV for 6 hr, then 0.5 mg/min IV for 18 hr
  • Digoxin: 0.5 mg IV initially, then 0.25 mg IV q4h
  • Diltiazem: 0.25 mg/kg IV (usually 10 " 20 mg) over 2 min, followed in 15 min by 0.35 mg/kg IV over 2 min
  • Esmolol: 0.5 mg/kg IV over 1 min; maintenance infusion, 0.05 mg/kg/min IV over 4 min, then 0.1 " 0.2 mg/kg/min IV continuously
  • Lidocaine: 100 mg IV
  • Metoprolol: 5 " 15 mg slow IV push at 5-min intervals to total of 15 mg
  • Procainamide: 20 " 30 mg/min IV up to 17 mg/kg, may increase to 50 mg/min for more urgent situations
  • Propranolol: 0.1 mg/kg div. into equal doses at 2 " 3-min intervals
  • Sotalol: Load 10 mg/min IV up to 1 " 1.5 mg/kg body weight
  • Verapamil: 2.5 " 5 mg IV bolus over 2 min; may repeat with 5 " 10 mg q15 " 30min to max. of 20 mg

Follow-Up

Disposition

Admission Criteria

  • Possible cardiac ischemic event
  • Persistent SVT
  • Possible pre-excitation syndrome
  • Other underlying metabolic abnormalities

Discharge Criteria

Terminated rhythm without organ hypoperfusion

Issues for Referral

If there are no concerns for underlying cardiac disease or metabolic derangement, a patient with uncomplicated SVT that is successfully treated may be discharged to follow-up with a primary doctor or cardiologist.

Followup Recommendations

The patient should return to the ED if feeling faint, dizzy, numbness or weakness of the face or limbs, or trouble seeing or speaking. Avoid high-risk activities (swimming, piloting, diving, etc.) until further evaluation.

Pearls and Pitfalls

  • Valsalva maneuvers should, ideally, be attempted with the patient lying flat. Despite the modest likelihood of success, the maneuver is simple and efficient.
  • AF is the most worrisome rhythm in patients with an accessory pathway such as WPW. At high ventricular rates, AF can appear deceptively regular, but should not be mistaken for benign SVT.
  • When adenosine has no apparent effect, an escalating dose beyond 12 " 18 mg, is sometimes used. However, if any lower adenosine dose transiently slows the heart rhythm, but the fast rate quickly resumes, then an increased dose is not warranted and an alternative medication should be used.
  • A wide complex tachycardia of uncertain etiology should be treated as VT, typically with amiodarone and potentially with procainamide if an accessory pathway is possible.
  • Since procainamide can be administered at a maximum rate of 50 mg/min, it takes a minimum of 20 min to administer 1 g, or 30 min to administer 1.5 g. Therefore, request the medicine promptly to optimize timing of administration. If QRS widening or hypotension occur, slow the rate of administration or discontinue the medication.

Additional Reading

  • Colucci RA, Silver MJ, Shubrook J. Common types of supraventricular tachycardia: Diagnosis and management. Am Fam Physician. 2010;82(8):942 " 952.
  • Hood RE, Shorofsky SR. Management of arrhythmias in the emergency department. Cardiol Clin. 2006;24:125 " 133.
  • Katritsis DG, Camm AJ. Atrioventricular nodal reentrant tachycardia. Circulation. 2010;122:831 " 840.
  • Link MS. Clinical practice. Evaluation and initial treatment of supraventricular tachycardia. N Engl J Med. 2012;367(15):1438 " 1448.
  • Manole MD, Saladino RA. Emergency department management of the pediatric patient with supraventricular tachycardia. Pediatr Emerg Care. 2007;23(3):176 " 189.
  • Marill KA, Wolfram S, Desouza IS, et al. Adenosine for wide-complex tachycardia: Efficacy and safety. Crit Care Med. 2009;37(9):2512 " 2518.

See Also (Topic, Algorithm, Electronic Media Element)

Ventricular Tachycardia

Codes

ICD9

  • 427.0 Paroxysmal supraventricular tachycardia
  • 427.89 Other specified cardiac dysrhythmias

ICD10

I47.1 Supraventricular tachycardia

SNOMED

  • 6456007 Supraventricular tachycardia (disorder)
  • 67198005 Paroxysmal supraventricular tachycardia (disorder)
  • 233900001 Supraventricular tachycardia with functional bundle branch block (disorder)