In tracing "a" of Figure 1, there seems to be only one P wave in front of each QRS complex, suggesting sinus rhythm. However, during the compensatory pauses after the PVCs (↑) in tracing "b," there ...
Bidirectional ventricular tachycardia is quite rare, but pathognomonic for digoxin toxicity. This ECG has two distinct QRS morphologies alternating every other beat. The QRS complex duration is ...