Bidirectional Ventricular Tachycardia Overview
- Bidirectional ventricular tachycardia (BVT) is a rare ventricular dysrhythmia characterised by a beat-to-beat alternation of the frontal QRS axis.
- In the example above, 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).
- This rhythm is most commonly associated with severe digoxin toxicity.
- It may be the presenting rhythm in patients with familial catecholaminergic polymorphic ventricular tachycardia (CPVT).
- BVT has also been reported with herbal aconite poisoning.
- Multifocal ectopy and bidirectional VT secondary to digoxin poisoning
- Bidirectional VT due to digoxin toxicity
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.
- Menduiña MJ, Candel JM, Alaminos P, Gómez FJ, Vílchez J. Bidirectional ventricular tachycardia due to digitalis poisoning. Rev Esp Cardiol. 2005 Aug;58(8):991-3. Spanish [PMID: 16053836]
- Smith SW, Shah RR, Hunt JL, Herzog CA. Bidirectional ventricular tachycardia resulting from herbal aconite poisoning. Ann Emerg Med. 2005 Jan;45(1):100-1
- Richter S, Brugada P. Bidirectional ventricular tachycardia. J Am Coll Cardiol. 2009 Sep 22;54(13):1189.
- Napolitano C, Priori SG, Bloise R. Catecholaminergic Polymorphic Ventricular Tachycardia. 2004 Oct 14 [updated 2009 Jul 7]. In: Pagon RA, Bird TC, Dolan CR, Stephens K, editors. GeneReviews [Internet]. Seattle (WA): University of Washington, Seattle (1993) [PMID: 20301466]
LITFL Further Reading
- ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
- ECG A to Z by diagnosis – ECG interpretation in clinical context
- ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
- 100 ECG Quiz – Self-assessment tool for examination practice
- ECG Reference SITES and BOOKS – the best of the rest
- Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric
- Wagner GS. Marriott’s Practical Electrocardiography 12e
- Chan TC. ECG in Emergency Medicine and Acute Care
- Rawshani A. Clinical ECG Interpretation
- Mattu A. ECG’s for the Emergency Physician
- Hampton JR. The ECG In Practice, 6e