Supraventricular Tachycardia Flashcards
Define supraventricular tachycardia in adults.
A heart rate > 100 associated with narrow-complex QRS complexes (< 0.12 ms).
What length qualifies a QRS complex as narrow-complex?
< 0.12 ms
What are the clinical features of supraventricular tachycardia?
- HR > 100
- Dizziness, syncope
- Chest pain, palpitations
- Dyspnea
What narrow-complex tachycardias need to be considered in the differential for supraventricular tachycardia?
- AFib
- AFlutter
- AV-nodal reentry tachycardia
- Accessory pathway-mediated tachycardia (e.g. WPW, LGL)
- Multifocal atrial tachycardia
- Junctional tachycardia
What, in addition to the wide differential for sinus tachycardia and other narrow-complex tachycardias, should be considered in the differential for supraventricular tachycardia?
- Misdiagnosed wide-complex tachycardia
2. Monitor artifact
What is the management of supraventricular tachycardia?
- Check pulse, if no pulse proceed to pulseless arrest algorithm
- Ensure adequate oxygenation and ventilation
- Check ECG to identify rhythm and confirm rate with SpO2 tracing
- Assess patient stability
- If unstable, perform immediate synchronized cardioversion
- If stable and irregular, probably afib, aflutter or MAT, control rate with diltiazem or betablockers
- If stable and regular, attempt vagal maneuvers, proceed to adenosine IV push.
- If successfully converted probably reentry SVT.
- If unsuccessful with adenosine, possibly Afib, ectopic atrial tachycardia or junctional tachycardia –>use rate control with diltiazem, beta-blockers.
- Search for correctable cause
- Observe and arrange for cardiology follow-up
If a patient has supraventricular tachycardia, what signs would be consistent with deeming the patient unstable?
Altered mental status
Chest pain
Hypotension/shock
Dyspnea
How should one approach unstable SVT?
Immediate synchronized cardioversion using 100 to 200K with a monophasic waveform for atrial fibrillation, 50 to 100J for atrial flutter and other SVTs. If using biphasic, 120J is appropriate. Escalate subsequent doses of energy as needed.
If a patient presents with unstable atrial fibrillation, how should one approach treating it?
Immediate syncrhonized cardioversion using 100 to 200 J with monophasic waveform or 120J if using biphasic.
If a patient presents with unstable supraventricular tachycardia other than atrial fibrillation, how should one approach treating it?
Immediate synchronized cardioversion using 50 to 100J for atrial flutter and other SVTs aside from AFib. 120J if using biphasic. Escalate subsequent doses of energy as needed.
If a patient presents with a stable supraventricular tachycardia and the rhythm is irregular, what rhythms are likely and how should they be treated?
Probably atrial fibrillation or possible atrial flutter or MAT
Control the rate with diltiazem (0.25mg/kg IV) or beta-blockers (esmolol 0.5mg/kg or metoprolol 5mg IV q5min up to 15mg…careful if CHF.
If a patient presents with a stable supraventricular tachycardia and the rhythm is regular, what rhythms are likely and how should they be treated?
Attempt vagal maneuvers and adenosine 6mg rapid IV push followed by 12mg IV push if unsuccessful (may repeat this once.)
IF adenosine works, probably reentry SVT watch for recurrence and treat with more adenosine or AV-nodal blockers.
If adenosine doesn’t work, possibly AFlutter, EAT, or junctional tachycardia. Rate control with AV-nodal blockers.
What are correctable causes of supraventricular tachycardia?
Surgical manipulation of the heart/pericardium Digitalis overdose Electrolyte imbalances Hypothermia Acidosis Toxins
When should adenosine be used for treatment of supraventricular tachycardia and how much?
When the hemodynamics are stable and the rhythm appears regular. Give 6mg IV rapid push. If no conversion give 12mg and repeat once if needed. Also should be used if conversion is successful but recurs.
If a regular rhythm supraventricular tachycardia successfully converts with adenosine, what is the likely type of SVT?
Probably reentry SVT
