Differential Diagnosis of Differential Diagnosis of Tachycardias Tachycardias

Differential diagnosis of broad complex tachycardias

Criteria for the diagnosis of the presence of a broad complex tachycardia:

QRS >120ms = Broad Complex Tachycardia

QRS <120ms = Narrow Complex Tachycardia

TachycardiasTachycardias

Narrow QRSNarrow QRS

Sinus tachycardiaSinus tachycardia

Atrial tachycardiaAtrial tachycardia

Atrial fibrillationAtrial fibrillation

Atrial FlutterAtrial Flutter

AVRNTAVRNT

AVRTAVRT

SVTSVT

Broad QRSBroad QRS

Ventricular tachycardiaVentricular tachycardia

SVT with abnormal SVT with abnormal conductionconduction

Bundle branch blockBundle branch block

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Ventricular pre- Ventricular pre- excitationexcitation

Differential diagnosis of broad complex tachycardias

The rhythm strip taken from a single lead is generally insufficient to make a differential diagnosis between an SVT with aberrancy or VT. A 12 lead ECG is required for making an accurate diagnosis.

Differential diagnosis of broad complex tachycardias

The presence of anyone of the following confirms the diagnosis of VT:

Evidence of A.V.Dissociation….in the form of independent atrial activity.

Presence of fusion beats

Presence of capture beats

AV dissociationAV dissociation

Atrioventricular dissociation in Atrioventricular dissociation in monomorphic ventricular tachycardia monomorphic ventricular tachycardia (note P waves, arrowed)(note P waves, arrowed)

Capture beatCapture beat

Capture beatCapture beat

Fusion BeatFusion Beat

Fusion beatFusion beat

Differential diagnosis of broad complex tachycardias

In patients with IHD…. …. 90% of broad complex tachycardias will be ventricular in origin

QRS Contours Favouring Ventricular Tachycardia

Wellens Gulamhusein

15/15 (100%) 84/86 (98%)

7/7 (100%) 177/187 (95%)

27/31 (87%) 189/190(100%)

17/17 (100%) 38/40(94%)

Wagner (2001) Marriotts Practical Electrocardiography 10th Ed.

V1

V1

V6

V6

Differential diagnosis of broad complex tachycardias

QRS Contours Favouring Ventricular Aberration

Wellens GulamhuseinV1

V6

38/41 (93%) 55/55 (100%)

44/47 (94%) 27/27 (100%)

Wagner (2001) Marriotts Practical Electrocardiography 10th Ed.

Differential diagnosis of broad complex tachycardias

Tachycardias presenting with a basically RBB pattern

V1R’ SVT is more the likely

diagnosis where there is a triphasic QRS…rSR’; with the R’ wave taller than the initial r.

Professor A.J Camm: “A Master Class in The Differential Diagnosis of Broad Complex Tachycardias.

Differential diagnosis of broad complex tachycardias

Tachycardias presenting with a basically RBB pattern

V1 S

If the ‘S’ wave at least reaches the isoelectric line (or goes beyond it) the tachycardia is most likely to be supra- ventricular in origin.

Professor A.J Camm: “A Master Class in The Differential Diagnosis of Broad Complex Tachycardias.

Tachycardias presenting with a basically RBB pattern

Differential diagnosis of broad complex tachycardias

V1 S

NB: Proviso:

If the ‘S’ wave is not much more than a notch on the down-stroke, then the tachycardia is less likely to be supraventricular in origin.

Professor A.J Camm: “A Master Class in The Differential Diagnosis of Broad Complex Tachycardias.

Tachycardias presenting with a basically RBB pattern

Differential diagnosis of broad complex tachycardias

V6R:S >1

SVT

R:S <1

VT

Professor A.J Camm: “A Master Class in The Differential Diagnosis of Broad Complex Tachycardias.

Tachycardias presenting with a basically LBB pattern

Differential diagnosis of broad complex tachycardias

Kinwall Criteria:

The Presence of any one of these characteristics points to the diagnosis of VT.

Initial ‘r’ wave in V1 > 30ms in duration.

Presence of a ‘notch’ on the down-stroke of the ‘S’ wave.

The duration of the complex from the start of the ‘r’ wave to the nadir of the ‘S’ wave = 60ms or more.

V1

Tachycardias presenting with a basically LBB pattern

Differential diagnosis of broad complex tachycardias

30ms

60ms

‘notch’

V1

Professor A.J Camm: “A Master Class in The Differential Diagnosis of Broad Complex Tachycardias.

Tachycardias presenting with a basically LBB pattern

Differential diagnosis of broad complex tachycardias

The presence of any ‘q’ wave points to the likelihood that the tachycardia is ventricular in origin.V6

‘q’

Professor A.J Camm: “A Master Class in The Differential Diagnosis of Broad Complex Tachycardias.

Differential diagnosis of broad complex tachycardias

Brugarder et al Criteria:

‘rS’ patterns are usually present in one or more precordial leads therefore:

A no ‘rS’ pattern most likely suggests that the tachycardia is ventricular in origin.

If there are any ‘rS’ complexes; if the distance from the start of the ‘r’ wave to the ‘nadir’ of the ‘S’ wave is 100ms or more it indicates that the tachycardia is most likely to be ventricular in origin.

Differential diagnosis of broad complex tachycardias

100ms

V1 V6

Professor A.J Camm: “A Master Class in The Differential Diagnosis of Broad Complex Tachycardias.

Differential diagnosis of broad complex tachycardias

Concordance of The QRS complexes in The Precordial Leads

“When all of the ventricular complexes from leads V1 to V6 are either negative (concordant precordial negative) or positive (concordant precordial positive), the diagnosis is most likely VT, since these patterns would be atypical of either RBBB or LBBB.”

Wagner (2001) Marriotts Practical Electrocardiography 10th Ed.

Differential diagnosis of broad complex tachycardias

Negative Concordance Positive Concordance

Wagner (2001) Marriotts Practical Electrocardiography 10th Ed.

Cardiac Axis:

If the Cardiac axis is between -1500 and -/+ 1800, this is clearly abnormal and is a useful clue to the tachycardia being ventricular in origin since the electrical axis of neither RBBB or LBBB produce such extreme axis deviation.

Broad complex Tachycardia

Independent p waves visible

VT

Are QRS in V1 and V6 typical for left or right BBB

SVT a possibilty

VT

yes

no

yes

no