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Difficulty: MediumCardiovascular System

A 32-year-old woman presents to the emergency department complaining of sudden-onset, rapid heart palpitations and mild chest fullness that began 30 minutes ago while sitting at her desk. She denies syncope, severe shortness of breath, or chest pain. Her blood pressure is 115/75 mm Hg, pulse is 185/min, and respiratory rate is 16/min. Physical examination reveals regular, rapid heart sounds with no murmurs. An electrocardiogram demonstrates a regular, narrow-complex tachycardia with no discernible P waves.

Arrange the following interventions in the most appropriate sequential order for managing this patient's arrhythmia, assuming each preceding step fails to restore sinus rhythm.

  1. 1Instruct the patient to bear down as if having a bowel movement (Valsalva maneuver)
  2. 2Administer a rapid intravenous push of adenosine
  3. 3Administer intravenous diltiazem or metoprolol
  4. 4Perform synchronized electrical cardioversion

Answer

The correct sequence for managing stable paroxysmal supraventricular tachycardia is to begin with vagal maneuvers, followed by intravenous adenosine, then intravenous AV nodal blocking agents (such as diltiazem), and finally synchronized electrical cardioversion if the arrhythmia is refractory to medical therapy.
The patient presents with paroxysmal supraventricular tachycardia (PSVT) and is hemodynamically stable. According to the ACLS algorithm, the least invasive method should be attempted first. Vagal maneuvers transiently increase parasympathetic tone to the AV node and can break the reentry circuit. If unsuccessful, adenosine is the first-line medication due to its rapid action and short half-life. If adenosine fails, longer-acting AV nodal blockers (non-dihydropyridine calcium channel blockers or beta-blockers) are indicated for rate control or chemical cardioversion. Synchronized electrical cardioversion is strictly reserved as a last resort in stable patients who are refractory to all medical therapies.

Step-by-Step Solution

1
Assess the patient's hemodynamic status based on vital signs and presentation.
The patient has a normal blood pressure (115/75 mm Hg) and no signs of cardiogenic shock, altered mental status, or acute heart failure, indicating she is hemodynamically stable.
Hemodynamic stability determines whether immediate cardioversion is necessary versus a stepwise medical approach.
2
Evaluate the electrocardiogram findings.
The ECG shows a regular, narrow-complex tachycardia without P waves, which is diagnostic of paroxysmal supraventricular tachycardia (PSVT).
Identifying the specific rhythm guides the selection of the correct Advanced Cardiac Life Support (ACLS) tachycardia algorithm.
3
Determine the correct ACLS sequence for a stable, regular, narrow-complex tachycardia.
The algorithm dictates starting with vagal maneuvers, escalating to adenosine, then to long-acting AV node blockers, and finally to electrical cardioversion.
This sequence minimizes invasive and side-effect-prone treatments by attempting the safest, most rapidly reversible methods first.

Key Concept

Stepwise management of hemodynamically stable paroxysmal supraventricular tachycardia (PSVT)
Estimated Time:1m 0s
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Topics

Cardiovascular System

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