Key Points
Differential Diagnosis
- Sinus tachycardia:
- Sepsis
- Hypovolemia
- Pericardial tamponade
- Acute MI
- Drug intoxication
- Wide complex tachycardias:
- Distinguish between supraventricular with
- aberrancy or ventricular origins
Management
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 maneuver
- If this is unsuccessful, adenosine is the drug of choice.
- Adenosine 6 mg will convert 60–80% of SVT
Pediatric Considerations
- 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 °ø 15 sec
- Children: Valsalva: “Blow into straw”
- Aberrant conduction:
- WPW syndrome and AVNRT are 2 most common forms of SVT in children.
- Use verapamil only >1 yr of age.
Pregnancy Considerations
- 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
Critical Actions
▢ Large-bore IV access
▢ EKG
▢ Discussion with patient regarding side effects of adenosine
▢ Adenosine with rhythm strip
▢ Repeat EKG and vitals after breaking rhythm
