Paroxysmal supraventricular tachycardia: Difference between revisions
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**Hypoxia, [[pulmonary embolism]]
**Hypoxia, [[pulmonary embolism]]
**Pre-existing heart disease (prior [[MI]], MVP, [[pericarditis]]) is rare
**Pre-existing heart disease (prior [[MI]], MVP, [[pericarditis]]) is rare
*Troponins are not indicated in patients without significant risk factors for CAD<ref>Bukkapatnam et al. Relationship of myocardial ischemia and injury to coronary artery disease in patients with supraventricular tachycardia. Am J Cardiol. 2010 Aug 1;106(3):374-7.</ref>


[[File:Hr scan.jpg|thumb|Termination of PSVT following adenosine]]
[[File:Hr scan.jpg|thumb|Termination of PSVT following adenosine]]

Revision as of 14:52, 9 March 2019

SVT terminology can be confusing, as some references consider SVT to be any rhythm originating above the ventricles (e.g. sinus tachycardia, MAT, atrial flutter, atrial fibrillation, PSVT, etc). As these entities have their own specific articles and treatment, only paroxysmal supraventricular tachycardia links here.

Background

  • Most common dysrhythmia in children and young, otherwise healthy patients
  • Also known as PSVT and frequently referred to just as SVT
  • Subtypes include AV nodal reentrant tachycardia (AVNRT) and AV reentrant tachycardia (AVRT)

Clinical Features

Differential Diagnosis

Palpitations

Evaluation

PSVT at ~180 bpm
Symptoms Sinus tachycardia SVT
History Volume loss Sudden onset
Physical Exam Dehydrated CHF-like
^Heart Rate (generally) <180 >180
Variability Yes No

^In infants HR cuttoff = 220

  • ECG findings
    • P-waves
      • Sinus tachycardia - may be seen before QRS complexes
      • SVT - either p-waves not seen OR retrograde p-waves
    • Signs with no actionable clinical relevance, unless they persist after conversion:
      • ST depressions in any lead
      • ST elevation in aVR
      • SVT is very rarely isolated manifestation of ACS and ST changes usually resolve after PSVT is appropriately treated
  • Consider PSVT underlying causes to include[1]:
  • Troponins are not indicated in patients without significant risk factors for CAD[2]
Termination of PSVT following adenosine

Unstable Management

  • Synchronized cardioversion 0.5-1.0 J/kg
  • Pediatrics: cardioversion at 0.5-1 J/kg. If unsuccessful, increase to 2 J/kg
  • Consider giving sedation prior to cardioversion if it will not significantly delay the procedure

Stable Management

Vagal maneuvers

  • Modified Positional Valsalva more successful than normal Valsalva maneuver[3]
  • Consider having legs all the way over the patient's head, which is even more than the [[modified positional valsalva, if patient can tolerate[4]
  • Pediatrics: often successful with ice application to face
  • Carotid sinus massage (ideal duration of 15 seconds[5])
    • Auscultate to rule out bruits in carotid artery before performing
    • Perform ONE side at a time
Legs over head PSVT.jpeg

Diving Reflex

  • More effective in infants
  • If pediatric patient can tolerate it, apply cold ice pack over face for 15-30 seconds, covering nose
  • Be conscientious of infants as obligate nasal breathers

Adenosine

  • Adults: 6mg IVP (1st dose) → 12mg (2nd dose) IV push (if initial dose fails)
  • Pediatrics: 0.1mg/kg (1st dose) → 0.2mg/kg (2nd dose) IV push (if initial dose fails)
  • Contraindicated in asthmatics
  • Some literature to support 3rd dose of 18mg if 12mg fails[6]
  • May decrease initial dose to 3mg if[7]:
    • Central line
    • Heart transplant
    • Taking carbamazepine or dipyridamole

Calcium-channel blockers

Adults

  • Diltiazem 15–20mg IV over 2min
    • May give 25mg IV if inadequate response after 15min
    • If IV bolus worked start IV infusion at 5–20mg/hr
    • A slow infusion of 2.5 mg/min to a maximum of 50 mg is also an option
      • In this trial 50% had converted by 12 mg and 75% had converted by 18 mg[8]
    • Contraindications: Hypotension, CHF, any suspicion of VT
    • Consider calcium gluconate premedication OR afterwards if BP falls
  • Phase 2 trial completed on intranasal CCB (Etripamil)[9]
    • high conversion rate (65 to 95%)
    • median time to conversion 3 minutes

Pediatrics

  • Verapamil 1-4 mg/kg q8hrs (only if >12 months old)[10]
  • May cause significant hypotension in infants

Beta-blockers

Adults

  • Metoprolol 5mg IV q5min x 3; give 50mg PO if IVP effective
  • Esmolol 500mcg/kg IV over 60sec
    • May give repeat bolus if inadequate response after 2-5min
    • If effective start infusion at 50mcg/kg/min (titrate up to 300mcg/kg/min)

Pediatrics

Disposition

  • Most can be discharged
    • Avoid stimulants, sympathomimetics
    • Consider low dose beta-blocker prescription, beta-1 specific (atenolol, metoprolol)
    • Follow up with primary care provider if first episode
    • Follow up with cardiology if recurrent episodes
  • A retrospective review of 111 patients found[11]:
    • 79 (71%) were discharged from the ED
      • 3 (4%) in this group had recurrent SVT after discharge
      • None had an unstable event
    • 32 (29%) were admitted to the hospital
      • 6 of the 32 (19%) had recurrent PSVT in the hospital
    • Recurrence more likely to occur in older patients and those with CVD

See Also

External Links

Amal Mattu ECG Case: Feb 26 2012

References

  1. ↑ Gugneja M et al. eMedicine. Paroxysmal Supraventricular Tachycardia. Dec 30, 2015. http://emedicine.medscape.com/article/156670-overview#a5.
  2. ↑ Bukkapatnam et al. Relationship of myocardial ischemia and injury to coronary artery disease in patients with supraventricular tachycardia. Am J Cardiol. 2010 Aug 1;106(3):374-7.
  3. ↑ Appelboam A. et al. Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial fulltext
  4. ↑ Schwartz AC. News: An Effective Maneuver to Break PSVT. Emergency Medicine News: March 2017 - Volume 39 - Issue 3 - p 28.
  5. ↑ Appelboam, A, et al. Randomised Evaluation of modified Valsalva Effectiveness in Re-entrant Tachycardias (REVERT) study. BMJ, 2014; 4(3):e004525.
  6. ↑ Weismuller P et al. Terminating supraventricular tachycardia with adenosine--comparing the effectiveness of 12mg and 18mg. Dtsch Med Wochenschr. 2000 Aug 18;125(33):961-9.
  7. ↑ ACLS Algorithms. https://acls-algorithms.com/acls-drugs/acls-and-adenosine/.
  8. ↑ Lim SH, Anantharaman V, Teo WS, Chan YH. Slow infusion of calcium channel blockers compared with intravenous adenosine in the emergency treatment of supraventricular tachycardia. Resuscitation. 2009 May;80(5):523-8. doi: 10.1016/j.resuscitation.2009.01.017. Epub 2009 Mar 3.
  9. ↑ Stambler, B. S., Dorian, P., Sager, P. T., Wight, D., Douville, P., Potvin, D., … Plat, F. (2018). Etripamil Nasal Spray for Rapid Conversion of Supraventricular Tachycardia to Sinus Rhythm. Journal of the American College of Cardiology, 72(5), 489–497.
  10. ↑ 10.0 10.1 10.2 Salerno, J et al. Supraventricular Tachycardia Arch Pediatr Adolesc Med. 2009;163(3):268-274.
  11. ↑ Luber S, Brady WJ, Joyce T, et al. Paroxysmal supraventricular tachycardia: outcome after ED care. Am J Emerg Med. 2001; 19(1):40-42.
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