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
  • Bidirectional VT due to digoxin toxicity

Example 3

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

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) Adult/Paediatric 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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