Junctional parasystole and pseudo-AV block

This complicated rhythm strip shows normal sinus rhythm and a competing junctional parasystolic focus. Solid circles indicate junctional premature beats from the parasystolic focus. Open circles indicate non-conducted junctional prematures; the first open circle is a nonconducted junctional premature that nevertheless interferes with AV conduction, thus creating the picture of AV block....i.e., pseudo-AV block.