ACLS review: SVT part 6

Synchronized cardioversion

·         Specific timed delivery of electrical shock to the heart

·         Treatment of choice for SVT, VT with a pulse and atrial flutter with evidence of poor profusion

·         Provide sedation and analgesia

·         Prepare to defibrillate immediately if cardioversion causes VF

Note

Synchronized cardioversion is shock delivery that is timed (synchronized) with the QRS complex. This synchronization avoids shock delivery during the relative refractory period of the cardiac cycle when a shock could produce VF.

 

Indications

·         All tachycardias (rate >150 bpm) with serious signs and symptoms related to the tachycardia.  These include unstable SVT, atrial flutter, atrial fibrillation and unstable VT

·         May give brief trial of medications based on specific arrhythmias.

Note

Cardioversion is less likely to be effective for treatment of junctional tachycardia or ectopic or multifocal atrial tachycardia because these rhythms have an automatic focus, arising from cells that are spontaneously depolarizing at a rapid rate

Precautions

·         In critical conditions go to immediate unsynchronized shocks.

·         Urgent cardioversion is generally not needed if heart rate is over 150 bpm.

·         Reactivation of sync mode is required after each attempted cardioversion (defibrillators/cardioverters default to unsynchronized mode).

·         Prepare to defibrillate immediately if cardioversion causes VF.

·         Synchronized cardioversion cannot be performed unless the patient is connected to monitor leads; lead select switch must be on lead I, II, or III and not on “paddles.”


Reviewed 2/28/16