Chapter 18: Acute Management of Supraventricular Tachycardia

BACKGROUND

Pregnancy is associated with increased arrythmia burden, and parturients with a history of arrythmia are at significant recurrence risk.¹

Supraventricular tachycardia (SVT) includes a range of tachyarrythmias originating from a circuit or focus involving the atria or the atrioventricular node.^2,3 It manifests as a narrow complex (QRS < 120 ms), regular tachycardia.

PRESENTATION

Symptoms may include palpitations, lightheadedness, dizziness, syncope, dyspnea, and chest pain. May have abrupt onset (with or without abrupt termination). Prompt and correct diagnosis of SVT is necessary for efficient treatment. (See Table 18-1.)

MANAGEMENT (FIG. 18-1)

• Assess hemodynamic status; stable or unstable?

  • Telemetry (pulse audible).

  • Blood pressure (repeated every 3 minutes).

  • Pulse oximeter, may require supplemental oxygen and/or endotracheal intubation (if unstable).

  • Left uterine displacement.

  • 12-lead EKG (if hemodynamically stable).

  • Establish intravenous access.

• Treatment¹:

  • Call for help, CODE CART nearby with pads.

  • Vagal manuevers recommended first-line treatment for hemodynamically stable SVT^4,5:

    • Valsalva (hold for 10 to 30 seconds; may be limited by patient participation).^6,7

    • Carotid sinus pressure (auscultate for bruit prior; make sure to press high enough on neck) → manual pressure for 5 to 10 seconds.^6,7

  • Adenosine recommended first-line pharmacologic treatment for hemodynamically stable SVT^5,8:

    • Make sure pads are placed prior to medication administration (pauses can cause arrythmias, need to be ready for emergent cardioversion/defibrillation).

    • Synchronize to QRS complex (ensure NOT synchronized to T-wave).

    • Press “Print” button on cardioverter/defibrillator.

    • Administer adenosine 6 mg intravenously (IV) (half-life ∼10 seconds) with rapid normal saline flush then lift arm immediately after administration to centrally distribute. If no effect, administer adenosine 12 mg IV in similar fashion.^4,8

    • Common side effects include transient flushing, chest pain.⁴

  • Beta-blockers recommended when adenosine is ineffective or contraindicated, and patient remains hemodynamically stable^5,8:

    • Slow infusion is less likely to cause hypotension.^4,5,9

    • Metoprolol: 2.5 to 5 mg IV over 2 minutes; may repeat in 10 minutes (up to 3 doses)⁴ OR

    • Propanolol: 1 mg IV over 1 minute; may repeat 1 mg every 2 minutes (up to 3 doses).⁴

  • Calcium channel blockers are reasonable for acute treatment when adenosine and beta-blockers are ineffective or contraindicated⁵:

    • Increased risk of hypotension and/or tocolysis.

    • Verapamil...