Escape beats occur upon failure of the normal cardiac pacemaker. For example if the sinus node fails to pace or to conduct to the ventricles, the ventricles may "escape" by picking up a rhythmn from an alternative pacemaker site. It is important to be able to distinguish between a premature contraction and an escape beat.
Take a close look at the following diagram:
This is an example from a patient whose heart was being electronically paced. Upon switching off the pacemaker there was an extended pause before the next natural depolarisation from a: ventricular or a junctional pacemaker. (click on the appropriate option)
In cases of third degree heart block (inability of the AV junction to conduct an action potential, ventricular escape is likely to occur.
To ventricular fibrillation
Back to the conduction system
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