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WCT.pptx
1. APPROACH TO A WIDE
COMPLEX
TACHYCARDIA
DR.MAKSUD
D-CARD Student
DHAKA MEDICAL COLLEGE
2. APPROACH TO A WIDE
COMPLEX
TACHYCARDIA
DR.MAKSUD
D-CARD Student
DHAKA MEDICAL COLLEGE
3. 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
4. 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
5. 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
6. 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”
7. 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”
9. r
DRUGS AGGRAVATE VT
Sympathomimetics:Noradrenaline,salbutamol,theophylines,
Antiarrythmics:class Ia & Ic
Cardiac glycosides
Antidepressant
Antibiotics
Baerman JM et al. Ann Emerg Med 1987;16:40-3
12. WIDE COMPLEX TACHYCARDIA:ECG
AV dissociation,
QRS morphology
QRS axis in frontal plane
QRS width
Capture beats
Fusion beats
Baerman JM et al. Ann Emerg Med 1987;16:40-3
13. • 69% of VT
s 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
14. • 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
15. 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
16. 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
18. 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
19. 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
21. Most specific ECG criteria
CompleteAVD in 20-50% of all VT
s
Specificity-100%; sensitivity- 20-50%
A/V ratio <1 equally diagnostic of VT
(V>>A)
2:1 retrograde conduction or
Wenckebach- 15 – 20% of VT
s
•
•
•
•
•
Clue for AVD- variation in QRS amplitude
during WCT
AF coexisting with VT - difficult to
diagnoseAV dissociation
•
•
24. 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 WCT
s
SVT
s 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
26. Concordance in precordial
V1 to V6 - Positive or negative concordance
leads
Present only in 20% of all VT
s
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 WCT
s)
mediated
27. 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
28. 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
30. 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
31. Wellens criteria of RBBB
Published in 1978
Simultaneous analysis of ECG and His-bundle electrograms
Analyzed EP proved 70 sustained VT and 70 SVT
s with aberrancy
Wellens HJJ et al, Value of ECG in WCT
.Am J Med 64:27-33,1978
32. 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%)
33. 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
34. 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
35. Brugada criteria
Brugada P et al. A new approach to the differential diagnosis of WCT
. Circulation. 1991;83: 1649-59
36. 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
37. Pava criteria
Published in 2010
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
38. Garner et al, WCT
.Arrhythmia & Electrophysiology review 2013;2(1):23-29
39. Steurer et al. VT vs Pre-excited SVT
. Clin Cardiol 1994;17:306-8
50. T
ake home
AV relationship:
AV dissociation
N
O
message
Step 1:
YES VT
Step 2:
Rightward superior axis
N
O
Vi/Vt ratio >1
VT
YES
SVT
YES
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