This is present in only a small percentage of VT ECG tracings, but it is diagnostic of VT. Frequently, this is difficult to see due to the fast rate of the QRS complex. Below is an ECG strip of a ...

See the ventricular tachycardia review below for a 12-lead ECG tracing of bidirectional ventricular tachycardia in a patient with digoxin toxicity.

Figure 18B shows the 12-lead ECG of the entrainment tracing of Figure 18A ... because it was originally studied in the context of VT origin localization (see the second part of this review).