Diagnostic criteria

  Only one of three, four or more P waves is conducted to the ventricles.

 
Most of the P waves are not followed by a QRS complex.





ECG 1a. The patient's cardiac rhythm on admission is atrial tachycardia, complete AV block and nodal rhythm (narrow QRS
rhythm).
P waves are regular but the rate is > 100/minute . P waves are NOT related to QRS complexes .
Narrow QRS complexes
denote nodal rhythm
.


Click here for a more detailed ECG



ECG 1b. Next day, his ECG shows 2:1 AV block. Her
Only 1 of every 2 P waves can be conducted to the ventricles.


Click here for a more detailed ECG



ECG 1c. 3:1 AV block (high degree AV block). Only one of every 3
P waves can be conducted to the ventricles.
The PR intervals of the conducted P waves are fixed (200 ms).


Click here for a more detailed ECG



ECG 1d. The same patient's ECG 4 days later: complete AV block and nodal rhtyhm (narrow QRS rhythm) is seen but now
there is no atrial tachycardia.
P waves are regular but not tachycardic . P waves are not related to the QRS complexes .


Click here for a more detailed ECG





ECG 2. 5:1 AV block (high degree AV block). Only
1 of every 5 P waves can be conducted to the ventricles, while 4 of them
cannot be conducted.


Click here for a more detailed ECG





ECG 3. The ECG above belongs to a 76 years-old woman with coronary artery disease and
left ventricular systolic dysfunction (LVEF 35%).
Atrial rate is above 100/minute: atrial tachycardia.
Of every 3 P waves, only one of them is conducted to the ventricles (high degree AV block)
with prolonged PR interval and aberration.
In this tracing, only
one P wave is conducted with a normal PR interval and without aberration.

Click here for a more detailed ECG