Approach to ECGs - VT vs. SVT - Wide Tachycardias

DDx = VT vs. SVT with BBB

All of the below are specific but not sensitive for VT:

 - No RS complexes (i.e. entirely positive or negative) in V1 -V6

 - Absence of typical RBBB or LBBB morphology

 - Extreme axis deviation ("northwest axis") — QRS is positive in aVR and negative in I + aVF.

 - Very broad complexes (> 160ms)

 - AV dissociation (P and QRS complexes at different rates)

 - Capture beats- a QRS complex of normal duration.

 - Fusion beats - a sinus and ventricular beat coincides to produce a hybrid complex.

 - Brugada's sign - The distance from the onset of the QRS complex to the nadir of the S-wave is > 100ms

 - Josephson's sign - Notching near the nadir of the S-wave

 - RSR' complexes with a taller left rabbit ear. This is the most specific finding in favour of VT. This is in contrast to RBBB, where the right rabbit ear is taller.



#VT #VTach #SVT #Comparison #VentricularTachycardia #Versus #ecg #ekg #cardiology #diagnosis #electrocardiogram