ECG Quiz 39

ECG Quiz 39

Though there is superficial resemblance to 2:1 AV block, it is actually complete AV block as illustrated in the lead II rhythm strip at the bottom of the tracing. All the four criteria for complete heart block on ECG are satisfied:

1. Regular PP interval
2. Regular RR interval
3. PP interval shorter than RR interval (atrial rate higher than ventricular rate)
4. Totally varying PR interval

Narrow QRS escape rhythm indicates that the level of the block is above the His bundle (supra Hisian block). A good ventricular rate and supra Hisian block in this ECG from a child are features of congenital complete heart block. T wave inversion in anterior leads could be a juvenile pattern. If it is seen in an adult with an Infra Hisian block it would suggest a recent Stokes-Adam attack and consequent hypoxia. In that case one would expect much broader T wave inversions with a prolonged QT interval.