Wide complex tachycardia

APPROACH TO A WIDE
COMPLEX
TACHYCARDIA
DR.MAKSUD
D-CARD Student
DHAKA MEDICAL COLLEGE

Definitions
 WCT- A rhythm with a rate of ≥ 100/min and QRSd ≥120 ms
 VT - A WCT originating below the level of His bundle
 SVT – A tachycardia dependent on structures at or above the level
of His bundle
 LBBB morphology – QRSd ≥ 120 ms with predominantly negative
terminal deflection in V1
 RBBB morphology – QRSd ≥
in V1
120 ms with positive terminal deflection
Miller JM et al. The many manifestations of VT. J Cardiovasc Electrophys 3:88-107,1992

Supraventricular tachycardia
With aberrancy in His-Purkinje system
anterograde accessory pathway
bizarre baseline QRS
conduction
entECartefact imbalance
Garner et al, WCT.Arrhythmia & Electrophysiology review 2013;2(1):23-29

Why to recognize ?
 Misdiagnosing VT as SVT  IV
deterioration
verapamil or adenosine  hemodynamic
 Wrongly labelling SVT as VT  inappropriate chronic therapy
 Assumptions
 “WCT in a alert and hemodynamically stable patient must be SVT”
 ”Patients with VT are always unstable”

Misdiagnosing VT as SVT  IV
deterioration
verapamil or adenosine  hemodynamic
Wrongly labelling SVT as VT  inappropriate chronic therapy
a alert
and hemodynamically stable patient must be SVT”
”Patients with VT are always unstable”

 LookforacuteTriggers(newMI,hypo/hyperkalaemia,cardiacFailure,Drug toxicity,Mechanicalirritation)
History & examination
 H/OPrior MI (98% PPV for VT)
 H/O CHF (100% PPV for VT)
 H/O Recent angina (100% PPV for VT)
 Age .>35 years (92% sensitivity for VT)
Baerman JM et al. Ann Emerg Med 1987;16:40-3

r
DRUGS AGGRAVATE VT
 Sympathomimetics:Noradrenaline,salbutamol,theophylines,
 Antiarrythmics:class Ia & Ic
 Cardiac glycosides
 Antidepressant
 Antibiotics

r

12 LEAD ECG
CXR
BLOOD-CHECK K+,Mg2+,Ca2+
ABGs
ECHO
INVESTIGATION

WIDE COMPLEX TACHYCARDIA:ECG
 AV dissociation,
 QRS morphology
 QRS axis in frontal plane
 QRS width
Capture beats
Fusion beats

• 69% of VTs had
ms
QRSd > 140
• Antiarrhythmic
nonspecifically
QRSd of a SVT
drugs
widen
may
the
• VT with relatively narrow
 more
structural
QRSd (120-140 ms)
likely in pts without
heart disease
Wellens HJJ et al, Value of ECG in WCT. Am J Med 64:27-33,1978

• More leftward the axis more likely
the arrhythmia is VT
• Shift in QRS axis of >40 degrees
between the baseline rhythm and
WCT- s/o VT

V1 with RBBB pattern
RV does not participate in initial ventricular depolarization
So initial portion of QRS is not affected by RBBB aberration
rSr’, rR’, rsr’ and rSR’ in V1 are consistent with aberration
Monophasic R wave, broad R >30 ms with any terminal negative
 highly suggestive of VT
QRS, qR

V6 with RBBB pattern
In true RBBB aberration  delayed RV activation  small ‘s’wave in
V6 (relatively smaller RV mass as compared to LV)

Ventricular activation over LBB  qRs, Rs, or RS (R/S >1) in V6
So patterns different from these  rS, Qrs, QS, QR, monophasic R wave,
RS with R/S <1  VT

Large ‘S’ wave in V6 during VT  RV activation + larger LV activation
propagating away from V6


Garner et al, WCT. Arrhythmia & Electrophysiology review 2013;2(1):23-29

V1 with LBBB pattern
Normally LBB mediates initial part of ventricular depolarization
during baseline rhythm

Even in the presence of LBBB, there is rapid penetration of LV
His-Purkinje system

Initial forces mediated by RBB are relatively preserved
So LBBB aberration  rS, QS in V1


But initial forces  narrow ’r’ wave and rapid smooth descent to
nadir of ’S’ wave in QS will be present

So broad ‘r’ waves of rS or QS descent with a slow descent
to nadir of ‘S’ wave > 6o ms  s/o VT


V6 with LBBB pattern
Typical LBBB initial ’q’ wave in QRS is absent
So RR’ or monophasic R wave is seen during SVT-A
If QR, QS, QrS, Rr’ present  s/o VT

Most specific ECG criteria
CompleteAVD in 20-50% of all VTs
Specificity-100%; sensitivity- 20-50%
A/V ratio <1  equally diagnostic of VT
(V>>A)
2:1 retrograde conduction or
Wenckebach- 15 – 20% of VTs
•
•
•
•
•
Clue for AVD- variation in QRS amplitude
during WCT
AF coexisting with VT - difficult to
diagnoseAV dissociation
•
•

 Fusion beats : hybrid QRS complex due to ventricular
sources
activation from 2 different
 Imply the presence ofAV dissociation during WCT
 Most frequently observed during relatively slow WCTs
 SVTs with aberrancy have RS complex in at least one precordial lead
 Precordial RS absent  s/o VT
 Even if RS complex is present, R wave onset to S wave nadir >100 ms 
s/o VT

Concordance in precordial
 V1 to V6 - Positive or negative concordance
leads
 Present only in 20% of all VTs
 In most series, divided between positive and negative patterns
 Diagnostic of ventricular origin; specificity >90% , low sensitivity
 Negative concordance is nearly always VT
 Exception: Positive concordance seen in antidromic tachycardia
by LP or LL pathway(1-6% of all WCTs)
mediated

Concordance in limb leads
Predominantly negative QRS complexes in leads I, II, III Q
waves during WCT  s/o old MI  so VT is likely Patients
with post MI VT  maintain the baseline Q waves
Exception: Pseudo Q waves seen in AVNRT with retrograde P waves with
aberrancy
VT occurring with a baseline BBB  QRS during VT narrower than in
baseline rhythm
< 1% of all VTs
Contralateral BBB during baseline rhythm and WCT  s/o VT









Vi/Vt ratio
 SVT-A  only one portion of His-Purkinje system
is blocked
 Another portion mediates normal initial
ventricular activation
 First part of QRS (Vi) should have rapid voltage
changes as compared to terminal part (Vt)
 VT  Slow muscle to muscle spread of
activation at the onset of QRS Vt > Vi
 Vi/Vt <1  s/o VT
Garner et al, WCT. Arrhythmia & Electrophysiology review 2013;2(1):23-29

Sandler and Marriot criteria
 Published in 1965
 Analyzed 100 PVCs, 50 RBBB aberrancies & 100 fixed RBBBs
1. RB- Identical activation vector = SVT (PPV - 92%)
2. RB- An rSR’ where S crosses baseline = SVT (PPV-91%)
3. RB- Triphasic QRS = SVT (PPV-92%, specificity >90%)
4. RB,LB- Precordial concordance = VT (PPV- 89-100%, specificity-95-100%)
Sandler IA et al, Ventricular ectopy Vs aberration. Circulation 1965;31:551-6

Wellens criteria of RBBB
 Simultaneous analysis of ECG and His-bundle electrograms
 Analyzed EP proved 70 sustained VT and 70 SVTs with aberrancy
Wellens HJJ et al, Value of ECG in WCT.Am J Med 64:27-33,1978

1. AV dissociation = VT (PPV-100%, specificity- 100% )
2. RB- QRSd >140 ms = VT (PPV-89%,specificity-57-75%)
3. RB- Left axis = VT(PPV-88-94%, if axis > -90, PPV-98%)
4. RB- “Rabbit ears” Rsr’ = VT (PPV-100%)
5. RB- If V1 QRS is triphasic, R:S ratio in V6<1 =VT(PPV-
90%)

Kindwall criteria of LBBB
 First criteria specific to LBBB WCT
 High specificity, PPV >97%, poor sensitivity
 Presence of any 1 out 4 indicates VT
1. LB- V1 or V2 with initial R > 30 ms = VT
2. LB- V1 or V2 QRS onset to nadir of S wave
ms = VT
> 60
3. LB- V1 or V2 with notching of S wave downstroke
= VT
4. LB- Any Q in V6 = VT
Kindwall KE et al. Criteria for VT in WC LBBB morphology tachycardias.Am J Cardiol 1988;61:1279-83

Brugada criteria
• Published in 1991
• Applicable to all WCT without
limitation to any BBB pattern
• Stepwise fashion
• Stop further analysis if any step
suggests VT
• All 4 steps  98% accuracy
• Only steps 1 & 2 PPV- 81-92%
Brugada P et al. A new approach to the differential diagnosis of WCT. Circulation. 1991;83: 1649-59

Brugada criteria
Brugada P et al. A new approach to the differential diagnosis of WCT. Circulation. 1991;83: 1649-59

Vereckei
• Published in 2008
criteria for aVR
• Applicable to all WCT without
limitation to any BBB pattern
• From a single lead – aVR
• Stepwise fashion
• Stop further analysis
suggests VT
if any step
Vereckei A et al. New algorithm using only aVR for DD of WCT. Heart rhythm 2008; 5:89-98

Pava criteria
of lead II
 PPV- 98%, specificity – 99%
 Overall accuracy is 69% in later studies
• Applicable to all WCT without limitation to any BBB pattern
• From a single lead – II
• R wave peak in lead II: Interval from QRS onset to first change
(R or S peak) ≥ 50 ms = VT
in polarity
Pava LF et al. R-wave peak time at D II. Heart Rhythm 2010;7:922-6

Garner et al, WCT.Arrhythmia & Electrophysiology review 2013;2(1):23-29

Steurer et al. VT vs Pre-excited SVT. Clin Cardiol 1994;17:306-8

Take home
AV relationship:
AV dissociation
N
O
message
 Step 1:
YES VT
 Step 2:
Rightward superior axis
N
O
Vi/Vt ratio >1
VTYES
SVTYES
 Step 3:
N
O
Precordial RS pattern
NO
VT Step 4:
E
S
Precordial RS interval >100 ms
N
O
LBBB morphology criteria in V1 for
SVT
YES
 Step 5: VT
 Step 6: NO
VT
SVT

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