What are the three criteria to diagnose complete block?
- No conduction
- [Despite] a slow ventricular rate
- Atrial impulses probing all phases of the cardiac cycle
You can see above the "A" satisfies these criteria but "B" does not. What does "slow" in this context mean? The experts suggest that 45-50 is the upper limit of the ventricular rate. The reason is that any faster and you get into rate-related blocks. As an example, below we have two strips. The top one show a SR with a 1° AVB. The second strip shows what happened when this heart was paced just a little faster; he goes into CHB.
As always, feel free to give your feedback and answers in the comments below.