The differential diagnosis of a regular broad complex tachycardia is VT versus SVT with aberrant conduction (due to bundle branch block or Wolff-Parkinson-White Syndrome). For an in-depth review of differentiating between the two, see VT versus SVT.
RVOT tachycardia is a form of monomorphic VT originating from the outflow tract of the right ventricle or occasionally from the tricuspid annulus. It is most commonly a form of idiopathic VT, whereby no structural heart disease, metabolic/electrolyte abnormalities, or long QT syndrome can be found. It can also be seen in patients with Arrhythmogenic Right Ventricular Dysplasia (ARVD).
The RVOT is divided into rightward (free wall), anterior, leftward, and posterior (septal) parts. RVOT tachycardia can originate from any of these sites but all carry common ECG characteristics.
ECG features of RVOT VT:
- LBBB morphology
- Inferior axis
- rS complex in V1 and R complex in V6
- Precordial transition usually ≥ V3, with the exception of septal origin, which occurs at ≤ V3
Other general features of VT, such as AV dissociation, fusion and/or capture beats may also be present.