All ECG 80
- Atrial tachycardia with 2:1 conduction
- Digoxin toxicity
- Old anteroseptal MI
This ECG shows two P waves for every QRS complex. Also, the P waves do not have "sinus morphology" meaning they are NOT upright in lead II. The atrial rate is quite fast (about 160 beats/minute). Thus, the P waves are ectopic and the rhythm is an atrial tachycardia. Since there is 2:1 block, the overall heart rate (QRS complexes) is half of the atrial rate or about 80 beats/minute.
Recall that the two pathognomonic rhythms in digoxin toxicity are atrial tachycardia with 2:1 conduction and bidirectional ventricular tachycardia. Atrial fibrillation with a slow ventricular response is common as well. Note that digoxin toxicity can cause ANY arrhythmia EXCEPT rapidly conducted atrial arrhythmias (such as atrial fibrillation/flutter with a rapid rate).