VT versus SVT with Aberration - Interpretation Cheat Sheet

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Features favouring VT

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RBBB

LBBB

Taller 2nd R wave (R’)

R’

R

V1

V6

V1

V6

Deep Swave

S

Broad, deepS wave

S

Broad, clumsyR wave

R

● Absence of typical RBBB or LBBB morphology● AV dissociation (P and QRS complexes occur independantly of each other)

P P PP

● Presence of captured beats (normal sinus beat that is captured between a VT run) and fusion beats (hybrid complex of normal sinus beat and a ventricular beat colision)

Narrow QRScomplexcaptured

beat‘fusion beat’hybrid QRSmorphology

‘fusion beat’hybrid QRSmorphology

Narrow QRScomplexcaptured

beat

● Positive or negative concordance in all precordial leads, i.e. leads V1-6 show entirely positive (R) or entirely negative (QS) complexes.

Example of positive concordance in VT

RBBB morph. criteria in VT

V1

V6

LBBB morph. criteria in VT

Monophasic RQR

(biphasic QRS)

R > R’(taller left rabbit ear)

R < S wave(R:S < 1)

QS or QR(dominant Q)

Monophasic R(No q, s or r’)

V1orV2

V6

Initial r > 30 ms Onset or r tonadir of S > 60 ms

Notcheddownstroke

Any q wave QS or QR

pattern

Axis suggesting VT

Rt superior axis(+ve aVR, -ve I, avF)

Left axis inpresence of RBBB

Right axis inpresence of LBBB

Brugada algorithm

1. Positive or negative concordance2. Onset of R to nadir (lowest point) of S > 100 ms in any V lead

3. AV dissociation4. Morphology criteria: both V1,V6 suggest VT

Vany VT SVT

if not

if not

if yes

if yes

Standard patterns

Ref. Arrhythmia & Electrophysiology Review 2013;2(1):23-9

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