Which of the following is not a feature of complete heart block on the ECG:
a) Constant RR interval
b) Constant PP interval
c) Constant PR interval
d) PP interval shorter than RR interval
Correct answer: c) Constant PR interval
In complete heart block the atria and ventricle are totally dissociated. Hence PR interval is totally varying. Constant PR interval would mean sequential atrioventricular activation, which is absent in complete heart block.
Read more on electrocardiographic features of complete heart block at: https://cardiophile.org/electrocardiographic-features-of-complete-heart-block/