ACLS review

191. What is the difference in the way monomorphic VT and polymorphic VT is treated?

Monomorphic VT is treated with synchronized cardioversion with an initial shock of 100J.   Polymorphic VT is treated with an unsynchronized shock at 200J.  For both, if there is no response to the first shock, then increase the dose in a step wise fashion. 

192.  What is the difference between synchronized cardioversion and defibrillation?

With defibrillation an unsynchronized shock is delivered randomly anywhere within the cardiac cycle. 

These shocks use a higher energy level beginning at 200J

The shock is delivered as soon as the operator pushes the shock button on the defibrillator

Synchronized cardioversion uses a sensor to mark the R wave and delivers the shock on the QRS complex. 

Synchronized cardioversion uses lower energy levels than defibrillation.

During synchronized cardioversion there is a slight delay in delivering the shock after the operator pushes the shock button.  This allows the machine to synchronize with the peak R waves of the QRS complex.

193.  What two tachycardic rhythms will not usually respond to synchronized cardioversion?

Junctional tachycardia and multifocal atrial tachycardia will not usually respond to synchronized cardioversion because these rhythms arise from an automatic focus within the myocardium that is rapidly depolarizing.

194. What are some potential problems associated with synchronized cardioversion?

If the R waves are low in amplitude or the rhythm irregular, the monitor may not be able to identify and synchronize with the R wave peaks

Synchronization can take extra time to complete as the operator is required to apply both the adhesive pads and the monitor electrodes.

195.  What are two examples of wide complex tachycardia?

Monomorphic VT

Polymorphic VT


Reviewed 2/28/16