Bidirectional Ventricular Tachycardia (BVT)

Bidirectional ventricular tachycardia (BVT) is a rare ventricular dysrhythmia characterised by a beat-to-beat alternation of the frontal QRS axis. It is most commonly associated with severe digoxin toxicity

  • In the example below, you can see the QRS axis shifts 180 degrees from left to right with each alternate beat
  • Another possible pattern is alternating left and right bundle-branch block (see Figure 2 in the paper by Smith et al)
ECG Bidirectional Ventricular Tachycardia 2
Bidirectional ventricular tachycardia: Note alternating QRS axis with each beat

Causes

ECG Examples
Example 1
ECG Bidirectional Ventricular Tachycardia BVT 3
  • Multifocal ectopy and bidirectional VT secondary to digoxin poisoning

Example 2
ECG Bidirectional Ventricular Tachycardia BVT 4
  • Bidirectional VT due to digoxin toxicity

Example 3
CPVT Catecholaminergic Polymorphic Ventricular Tachycardia

Exercise stress test in a patient with CPVT:

  • Progressively worsening ventricular arrhythmias are observed during exercise
  • Typical bidirectional VT develops after 1 minute of exercise with a sinus heart rate of approximately 120 beats per minute
  • Arrhythmias rapidly recede during recovery


References

Advanced Reading

Online

Textbooks


LITFL Further Reading

ECG LIBRARY 700

ECG LIBRARY

Electrocardiogram

Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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