differentiating between supraventicular tachycardia and ventricular tachycardia in wide complex rhythm is always confusing and management is totally different. correct diagnosis will make dramatic difference in patient management.

1. WIDE COMPLEX
TACHYCARDIA-
SVT vs VT
DR MAHENDRA
CARDIOLOGY, JIPMER
1

2. 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 ≥ 120 ms with positive terminal deflection
in V1
2
Miller JM et al. The many manifestations of VT. J Cardiovasc Electrophys 3:88-107,1992

3. WCT- Differential Diagnosis
 Ventricular tachycardia (80%)
 Supraventricular tachycardia
 With aberrancy in His-Purkinje system
 With anterograde accessory pathway conduction
 With bizarre baseline QRS
 Drug or electrolyte imbalance
 Ventricular pacing
 ECG artefact
Garner et al, WCT. Arrhythmia & Electrophysiology review 2013;2(1):23-29
3

4. Why to recognize ?
 Misdiagnosing VT as SVT  IV verapamil or adenosine  hemodynamic
deterioration
 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”❌
4

5. History & examination
 H/O Prior 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)
 Variable S1 (s/o VT)
 Cannon ’a’ waves (favours VT)
5
Baerman JM et al. Ann Emerg Med 1987;16:40-3

6. • 69% of VTs had QRSd > 140
ms
• Antiarrhythmic drugs may
nonspecifically widen the
QRSd of a SVT
• VT with relatively narrow
QRSd (120-140 ms)  more
likely in pts without structural
heart disease
6
Wellens HJJ et al, Value of ECG in WCT. Am J Med 64:27-33,1978

7. • 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
7

8. 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 QRS, qR
 highly suggestive of VT
8

9. 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
9

10. 10
Garner et al, WCT. Arrhythmia & Electrophysiology review 2013;2(1):23-29

11. 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
11

12. 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
12

13. 13
Garner et al, WCT. Arrhythmia & Electrophysiology review 2013;2(1):23-29

14. • Most specific ECG criteria
• Complete AVD 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
diagnose AV dissociation
14

15.  Fusion beats : hybrid QRS complex due to ventricular activation from 2 different
sources
 Imply the presence of AV 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
15

16. Concordance in precordial leads
 V1 to V6 - Positive or negative concordance
 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 mediated
by LP or LL pathway(1-6% of all WCTs)
16

17.  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
17

18. 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
18
Garner et al, WCT. Arrhythmia & Electrophysiology review 2013;2(1):23-29

19. MORPHOLOGY CRITERIA
19

20. 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%)
20
Sandler IA et al, Ventricular ectopy Vs aberration. Circulation 1965;31:551-6

21. Wellens criteria of RBBB
 Published in 1978
 Simultaneous analysis of ECG and His-bundle electrograms
 Analyzed EP proved 70 sustained VT and 70 SVTs with aberrancy
21
Wellens HJJ et al, Value of ECG in WCT. Am J Med 64:27-33,1978

22. 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%)
22

23. 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 > 60
ms = VT
3. LB- V1 or V2 with notching of S wave downstroke
= VT
4. LB- Any Q in V6 = VT
23
Kindwall KE et al. Criteria for VT in WC LBBB morphology tachycardias. Am J Cardiol 1988;61:1279-83

24. 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%
24
Brugada P et al. A new approach to the differential diagnosis of WCT. Circulation. 1991;83: 1649-59

25. Vereckei criteria for aVR
• Published in 2008
• Applicable to all WCT without
limitation to any BBB pattern
• From a single lead – aVR
• Stepwise fashion
• Stop further analysis if any step
suggests VT
25
Vereckei A et al. New algorithm using only aVR for DD of WCT. Heart rhythm 2008; 5:89-98

26. Pava criteria of lead II
 Published in 2010
 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 in polarity
(R or S peak) ≥ 50 ms = VT
26
Pava LF et al. R-wave peak time at D II. Heart Rhythm 2010;7:922-6

27. Griffith algorithm
 Each ECG is analyzed for V1 and V6 criteria consistent with aberration
 If the criteria for aberration are not found, VT is assumed
 Good sensitivity, poor specificity
 Drawback: RVOT tachycardias as misclassified as SVT by this algorithm
27
Griffith MJ et al. Ventricular tachycardia as default diagnosis in broad complex tachycardia. Lancet 1994;343:386-8

28. 28
Garner et al, WCT. Arrhythmia & Electrophysiology review 2013;2(1):23-29

29. 29
Steurer et al. VT vs Pre-excited SVT. Clin Cardiol 1994;17:306-8

30. ECG-1 30

31. ECG-2 31

32. ECG-3 32

33. Take home message
 Step 1:
 Step 2:
 Step 3:
 Step 4:
 Step 5:
 Step 6:
33
AV relationship:
AV dissociation YES VT
N
O
Rightward superior axis
YES VT
N
O
Vi/Vt ratio >1 YES SVT
Precordial RS pattern
Precordial RS interval >100 ms
LBBB morphology criteria in V1 for
SVT
N
O
Y
E
S
N
O
NO
VT
VT
VTNO
SVT
YES

34. 34
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