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Zorluk: OrtaCardiovascular System

A 28-year-old female teacher presents to the urgent care clinic complaining of a suddenly 'racing heart' that began 30 minutes ago while she was grading papers. She denies chest pain, shortness of breath, or lightheadedness. Her blood pressure is 122/78 mm Hg, pulse is 175/min, and respiratory rate is 16/min. Oxygen saturation is 99% on room air. A 12-lead electrocardiogram demonstrates a regular, narrow-complex tachycardia with no discernible P waves. Assuming each subsequent step fails to terminate the arrhythmia, arrange the following therapeutic interventions in the correct stepwise order of administration for this patient.

  1. 1Instruct the patient to perform a modified Valsalva maneuver
  2. 2Administer a rapid intravenous push of adenosine
  3. 3Administer intravenous diltiazem or metoprolol
  4. 4Perform synchronized electrical cardioversion

Cevap

The correct sequential management for hemodynamically stable paroxysmal supraventricular tachycardia is to begin with vagal maneuvers (Valsalva), followed by intravenous adenosine, then an intravenous calcium channel blocker or beta-blocker, and finally synchronized electrical cardioversion if all other measures fail.
The established advanced cardiac life support (ACLS) algorithm for adult tachycardia with a pulse requires assessing hemodynamic stability first. Because this patient is stable with a regular, narrow QRS complex, the correct sequence escalates from least invasive to most invasive: vagal maneuvers, then adenosine, then longer-acting AV nodal blockers (like diltiazem), and finally synchronized cardioversion if medical therapy fails.

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1
Assess the patient's hemodynamic stability and rhythm type.
The patient has normal blood pressure, no signs of shock, and is fully alert. The ECG shows a regular, narrow-complex tachycardia indicating stable paroxysmal supraventricular tachycardia (PSVT).
Hemodynamic stability dictates the entire treatment algorithm. Unstable patients require immediate cardioversion, whereas stable patients follow a stepwise, least-invasive-first approach.
2
Select the initial, non-pharmacological therapy.
Instruct the patient to perform a modified Valsalva maneuver.
This is the safest initial step. It transiently increases vagal parasympathetic tone to the AV node, which can break the reentrant circuit responsible for PSVT.
3
Choose the first-line pharmacological agent if the non-pharmacological step fails.
Administer a rapid intravenous push of adenosine.
Adenosine acts primarily on the AV node to significantly slow conduction time. Its rapid onset and brief duration of action make it the ideal first-line medication.
4
Choose a second-line pharmacological agent if adenosine is ineffective.
Administer intravenous diltiazem or metoprolol.
If short-acting AV node blockade fails, longer-acting AV nodal blocking agents are necessary to attempt chemical conversion or rate control.
5
Determine the final intervention if the rhythm is entirely refractory.
Perform synchronized electrical cardioversion.
When a persistent tachycardia cannot be broken by medications, electrical cardioversion is required to restore normal sinus rhythm, even if the patient initially presented as hemodynamically stable.

Anahtar Kavram

Stepwise management of hemodynamically stable paroxysmal supraventricular tachycardia (PSVT)
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Cardiovascular System

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