wide complex tachycardia.pptx

WIDE QRS TACHYCARDIA
PRESENTED BY
DR. SRIKANTH N
DEPARTMENT OF CARDIOLOGY
NIMS HYDERABAD

Wide complex tachycardia
● Definitions
● Causes
● Featuresfor differentiation
● Diagnostic approach/algorithms

• Wide Complex Tachycardias (WCT) – QRS duration > 120 ms and heart
rate > 100 beats/min
• Less synchronous ventricular activation of longer duration which can
be due to intraventricular conduction disturbances ,ventricular
activation not mediated by his bundle but by bypass tract or site with
in ventricle
• Correct diagnosis is important for the acute as well as long term
management of patients
• Categories of WCTs include ventricular tachycardia (VT), SVT with
abnormal intraventricular conduction, and ventricular paced rhythms

Intra ventricular conduction delay
• Structural abnormality of his purkinje system
• Structural abnormality of ventricular myocardium
• Functional refractoriness in a portion of conduction system

Differential diagnosis
VT – 80% of Wide QRS Complex Tachycardia
SVT with abberancy 15 to 20%---functional BBB , pre existing BBB
Pre excited SVT– antidromic AVRT,AT or AVNRT with bystander bypass
tract – 1% to 6%
SVT with pre existing non aberration QRS abnormality
SVT with anti arrhythmic drugs---class IA,IC
Electrolyte imbalances-----Hyperkalemia
Ventricular pacing

age
• Age more than 35 years VT (PPV 85%)
• Age less than 35 years SVT(PPV 70%)

symptoms
• Mis diagnosis on the basis of symptoms and haemodynamic stability
is a common error that can lead to inappropriate and potentially
dangerous therapy.
• Duration recurrence over a period of more than 3 years SVT more
likely.

Underlying heart disease
• Post MI --98% VT
• 7% SVT
• VT can occur in those which structurally normal heart disease,
• SVT can occur in those with structural heart disease.

History
• History of pacemaker
• History of drugs --quinidine,sotalol,dofetilide,erythromycin,diuretics
leading hypokalemia and hypomagnesemia
• Digoxin---monomorphic VT,Biderectional VT,Non paroxysmal
Junctional tachycardia

examination
• Prominent a WAVE IN JVP SVT
• INTERMITTENT cannon A waves VT
• CAROTID SINUS MASSAGE—
AVRT/AVNRT CAN BE TERMINATED
VT cannot be terminated ,but atrial rate may be slowed
down, expose the av dissociation

ECG
• Rate: limited use in distinguishing VT from SVT as there is too much overlap
• Consider Atrial flutter when HR is ~150 beats/min
• Regularity: VT is generally regular, though there can be slight variation in
the RR intervals
• Slight irregularity at the onset (“warm-up phenomenon”) favours VT
• Grossly irregular WCT likely represents:
1) AF w/ aberrant conduction,,
2) AF w/ conduction over an accessory pathway,,
3) polymorphic VT
• Uniformity of the RR intervals favours SVT

●
●
A
Vdissociation :
The most specific ECG finding for VT .
Cluesfor A
Vdissociation:
1. ClinicallybycannonAwaves, variableintensity ofS1, Variation
in SBPunrelated to respiration.
2. A
Vdissociation
3. A
Vratio of lessthan 1
4. 2:1 V
Ablock(d/t retrograde conduction)
5. V
ariation in QRSamplitude duringWCT
6. Fusion &capture beats,dissociatedpwaves

ECG-AV DISSOCIATION
• Complete AVD occurs in 20-50% of all VTs
• 15-20% VTs have second degree AV block
• 30% of VTs have 1:1 retrograde conduction
• QRS complex amplitude variation,T wave changes
• Transient retrograde blocks can be induced by carotid sinus massage
• Prevalence varies due to
1. Tachycardia rate
2. Amount of ECG recording available
3. Observer experience
4. Observer confidence
• Use lewis leads, echocardiography, oesophageal electrode, transvenous electrode

Av dissociation
• Sub atrial SVT JUNCTIONAL ECTOPIC TACHYCARDIA
NODO FASCICULAR REENTRANT TACHYCARDIA

DISSOCIATE P WAVES
• P WAVE NOT VISIBLE----
• LEWIS LEAD
• OESOPHAGEAL LEAD,
• RA RECORDING,
• CAROTID SINUS MASSAGE,
• EP TESTING

● Featuresfor differentiation :
● Historyand physical examination:
1. H/o heart disease– previousMI, angina, CHF– have a PPA of
95%for diagnosingVT
2. Pts with VT are older than SVT (> 35 yrs)
3. SVT-Aoften have h/o previous episode(>3years)
4. Pts with SVT-Aare hemodynamicallystable.
5. Examination for A
Vdissociation
a. CannonAwaves in JVP
b. V
ariable S1intensity
c. Variation in SBPunrelated to respiration.
6. Termination ofWCT with physical manoeuvres(catotidsinus
massage) and medications (adenosisne)

FUSION, CAPTURE AND ECHO BEATS

● Featuresfor differentiation byECG :
1. QRSduration
2. QRSaxis
3. Concordant pattern
4. Precordial RSduration.
5. Morphological criteria - RBBB, LBBB
6. Q wave presence
7. A
Vdissociation
8. BaselineQRS prolongation – QRS duration , QRS configuration.
9. aVR changes.
10.Lead IIR-wave-peak-time (RWPT) criterion .

●
●
●
1. QRSduration :
> 160 ms with LBBB , >140 ms with RBBB - VT
Wellenset al . Showed that 69%of VT had QRSduration of
>140ms and none of SVT-Ashowed QRS duration of >140ms.
Exceptions:
a. Anti arrythmitic drugs non specifically prolong QRS duration.
b. Pts with structurallynormal heart mayhaveVT with QRS
duration of 120-140ms.(<140ms in12% , < 120 ms in 4%)
c. QRS duration also depend site of origin of VT, septal VTOR
FASICULARVT
QRS duration hassensitivity of 70%

●
●
●
●
2. QRSaxis:
Frontal plane axis of -90 to +180 --- VT
Shift in QRS axis of more than 40 from baseline --- VT(less
specific)
RBBBwith LAD, LBBBwith RAD --- VT.
RBBBwithnormalaxissuggestSVT.

●
●
3. Concordant QRSin chest leads:
Concordant QRSin chest leadsis diagnosticof VT uncommon in
SVT-A.(negativemoresuggestivethanpositive)
Exceptions:
●
● Positive concordance (ventricular activation begins left
posteriorly) seen in VToriginating in Lt post wall or SVTusing a
left posterior accessorypathway forA
Vconduction.
Ifno additional criteria for WPW are absent don’t consider it
because oflow incidence(<6%)
Specificity of 90%, Sensitivity of 20%

●
●
●
3. Concordant QRSin limb leads:
The presence of predominantly negative QRS complexes in leads
1,2,3 is suggestive ofVT
This isanother wayto describe right superior axis
Similar to RSaxis it is considered ashighlyspecific for VT

4. Pericardial RSduration criteria:
● Ifconcordant QRScomplexes are absent i.e with RScomplex
onset of R wave to nadir of Swave > 100 ms.
Sensitivity – 66%
Specificity - 98%

●
●
●
5. RBBB– V1 :
rSr , rSR , rR , rsr patterns consistent with SVT-A
R , R>30ms with any negative QRS, qR --- VT
Thisis because right ventricle doesn’t participate in initial QRS
Sensitivity – 30-80%
Specificity - 84-95%

5. RBBB– V6 :
● qRs , Rs , RSwith R/S >1 --- SVT –A
● R , QR, QS , RSwith R/ S< 1 --- VT
Sensitivity – 30-60%
Specificity - 80-100%

5. LBBB– V1,V6:
Sensitivity – 100%
Specificity - 89%
Sensitivity – 17%
Specificity - 100%

●
●
●
5. Ambiguous chest lead pattern:
W and Mpattern in V1 have been classified asLBBB&RBBB
Because theyare ambiguousin this way, theyare unlikelyto
represent typical aberration and are highlyspecificfor VT.
Sensitivityof 60-80%, specificity of90-95%.

●
●
●
6. Q wave presence :
Q duringWCT --- suggest old MI--- VTmost likely.
Ingeneralpts with post MIVTmaintainQ waveduringWCT that
are present during baseline in the same lead.
Exceptions:
1. Pts with DCMPwill have Q wave duringVT that are not present
during baseline.
2. PSEUDO Q wave with retrograde p wave deforming QRScan
be seen in SVT-A
3. Preexcited tachycardia with posteriorA
Vconnection can haveQ
wave in inferior leads

● Diagnostic approach/algorithms
1. Wellens(1978) , Akhtar(1988) ,
2. Brugada(1991)
3. Griffith(1994)
4. Bayesian(1995)
5. aVR algorithms(2007)
6. lead II R-wave-peak-time (RWPT) criterion(2010)
7. Combined .

Diagnostic approach/algorithms
Sensitivity– 98.7%
Specificity – 96.5%
BrugadaP
,BrugadaJetal.Anewapproachtothe
DDofaregulartachycardiawithawideQRS
complex. Circulation. 1991;83:1649-16595
BRUGADA CRITERIA

Lead IIR-wave-peak-time (RWPT) criterion : Pavas criteria
RWPT > or =50 ms at DII is a
simple and highlysensitive
criterion that discriminates VT
from SVT in patients with wide
QRScomplex tachycardia.
Heart Rhythm. 2010 Jul;7(7):922-6. Epub2010 Mar4.
Sensitivityand
specificity of 97%

Morphologic criteria
Initial R
more than
40ms
In the presence of LBBB like morphology
Capture beats
Fusion beats
Notch Any Q in V6
Rapid
downstroke
No q
LBBB
aberration

Morphologic criteria
In the presence of RBBB like morphology
Monophasic R in V1 Deep
RBBB

WELLENS CRITERIA AKHTAR CRITERIA

7. A
Vdissociation :
Vrate = 215/mt
Arate = 125/mt
A/V =0.58

7. A
Vdissociation :
VT with retrograde 2:1 V
Aconduction (seen in 15-20%ofVT)

● V
ariation in amplitude of QRSduringWCT
1. Scalar summation ofPwave with QRS
2. V
ariable ventricular filling in the presence ofA
VD
● Presence of multiple WCT configuration hasasensitivity of 55%
for diagnosingVT
7. A
Vdissociation :

● The QRS complex is prolonged, and the R-R interval is regular
except for occasional capture beats (C) that have anormal contour
and are slightly premature. Complexes intermediate in contour
represent fusion beats (F).
● Thus, even though atrial activity is not clearly apparent,
atrioventricular dissociation is present during ventricular
tachycardia and produces intermittent capture and fusion beats
7. A
Vdissociation :

7. A
Vdissociation :

7. A
Vdissociation :
● Caveatswhile usingA
VD:
1. Low sensitivity(20-50%) is d/t fast heart rates, inadequate
duration of recording , observer inexperience.
2. 30%ofpts , especiallyVTwith lowVrate , have1:1 V
A
conduction – differentiate by vagalmaneuvers , adnosine.
3. AFand VT co existA
VD cannot be diagnosed .
Sensitivity– 20-50%
Specificity – 98%

8. Base line QRSprolongation:
a. Pt with baseline QRSrhythm and WCT QRSdifferent – VT
1. QRSduringVT is narrower than baseline rhythm
2. Contralateral BBBin baseline rhythm and duringWCT
3. A
Vdissociation
4. Rarely other findings maybe useful like precordial concordance ,
north-west axis , monophasic R wave in V1
Ptswith BBRT Impulse originatesin RBB TravelsthroughLBB
Have typical featuresofLBBB

9. aVRchanges:
1. Presence of initial ‘r’wave in aVR
2. Presence of initial ‘r’or ‘q’wave of > 40ms duration
3. Presence of notchin descending limb of negative onset and
predominantlynegative QRS
4. Vi/Vt ≤ 1
All the above features are indicative ofVT
Specificity – 99%

9.
aVRchanges: Initial ‘r’
wave in aVR
DuringSVT with aberrancy,
initial septal activation and main
ventricular activation are
directed awayfrom lead aVR
negative QRScomplex
Exceptions:
1. Inferior MI- initial r wave (rScomplex) duringNSRor SVT
2. VToriginating from base of heart may not have initial r wave

9. aVRchanges: Vi/ Vt ≤ 1
● Vi = voltage in the initial 40ms of QRS
● Vt = voltage in the terminal 40msof QRS
● In SVT-Aonly one portion is bundle branch is blocked --- so the
initial portion of QRSis rapid compared to terminal portion.
● InVTslow muscle to muscle spread of impulse causes slower
voltage changesthroughout QRScomplex
● Can be applied to anylead
● The vi/vt was> 1 (signifyingsupraventricular origin) in 88%
tracingswith LBBBpattern, in 98% with RBBBpattern, and
90% with nonspecific IVCD.

9. aVRchanges: Vi/ Vt ≤ 1

PRECORDIAL RS ABSENT
• Absence of RS in any precordial lead in any lead suggests VT
• In a analysis of 554 WCTs (384 VTs and 170 SVTs) RS was absent in 83
(15%) all were VTs

V2
V3
V1
V4
V5
V6
Why absence of RS indicates VT ?

V1 V2
V3
V4
V5
V6

V1 V2
V3
V4
V5
V6
However, presence of RS does not preclude VT

Why RS interval 100 ms indicates VT ?
Normally ventricular activation speed up by the
virtue of Purkinje fibers
<100 ms

Why RS interval 100 ms indicates VT ?
Subepicardial origin of VT delay
ventricular activation
>100 ms
Again.. RS <100 ms does not preclude VT

WCT
NO YES
INDEPENDENTPWA
VES
YES
VT
Griffith MJ,GarrattCi,etVTasdefault diagnosisin
broadcomplextachycardia.Lancet1994 feb
Sensitivity – 95%
Specificity– 64%
GRIFFITH CRITERIA

Diagnostic approach/algorithms BAYESIAN CRITERIA
CRITERIA LR
QRS WIDTH
=140MS 0.31
140-160MS 0.48
> 160MS 22.86
QRS AXIS
NWAXIS 7.86
RBBB + LAD 8.21
LBBB + RAD 3.93
NONE 0.47
V WAVE IN RBBB
TALLER LT
PEAK
50
Rs OR qR 4.03
rsR OR rR 0.21
NONE 1.41
V WAVE IN LBBB
r > 40MS 50
NOTCH IN ‘S’ 50
R-S > 60MS 50
NONE 0.13
INTRINSICOID IN V6
= 60MS 19.3
< 60MS 0.46
V6 MORPHOLOGY
QS 50
BIPHASIC RBBB R/S<1 50
TRIPHASIC RBBB
R/S<1
0.13
Sensitivity – 95%
Specificity – 52%

Diagnostic approach/algorithms aVR CRITERIA
Heart Rhythm, , V
ereckei, A. et al. New
algorithmusingonlyleadaVRforDDof wide
QRScomplextachycardia., 2008
Specificity – 99%

Sen.10%
Spe.100%
Sen.48%
Spe.98%
Sen.89%
Spe.89%
Sen.95%
Spe.80%
The sensitivity [95.7 vs.
88.2, P< 0.001]and NPV
[83.5%vs. 65.3% for VT
diagnosis ofthe new
algorithmwere superior to
those of the Brugada criteria
Application of anewalgorithmin the DD
of wideQRScomplextachycardia Andra´s
V
ereckei et al . EHJ2007.

ALGORITHM ORIGINAL STUDY LAU & NG(2001)
ISENHOUR(2000) SEN. SPEF. SEN.
SPE. SEN SPE.
BRUGADA 98.7 96.5 92 44 79-91 43-70
GRIFFITH 95 64 92 44
BA
YESIAN 95 52 97 56

aVR algorithm
1) Evaluate for the presence of an initial R wave
2) Evaluate for the presence of an initial r or q wave with width > 40
msec
3)Evaluate for notching on the descending limb of a negative onset,
predominately negative QRS complex

● Comparison of five electrocardiographic methods for differentiation
of wide QRS-complex tachycardias
● Brugada,Bayesian,Griffith, andaVRalgorithms, andthe leadIIR-
wave-peak-time (RWPT) criterion
● All five algorithms/criteria had equal moderate diagnostic accuracy.
● The newer methods were not more accurate than the classic Brugada
algorithm
Comparison of five electrocardiographic methods for differentiation
of wide QRS-complex tachycardias.Jastrzebski.M Europace 2010 feb
14

● Best algorithmic approach for diagnosingWCT
1. BRUGADA
2. aVRcriteria
3. V
ereckei combined criteria(old &aVRcriteria)

Causes:
Regular :
1. V
entricular tachycardia(80%of WCT)
2. Any SVT with aberrancy(2n
dMCWCT)
3. Any SVT with BBB
4. AnySVTwith delayed conduction d/t drugs and electrolytes
a. ClassIA,IC ; hyperkalemia.
5. AntidromicA
VRT(1-5%) Irregular :
6.Pacemaker mediated rhythm
7. AFwith conduction on preexcitation pathway.
8. Any irregular SVT with aberrancy, BBB.
9. VTin the 1st30 sec , pts on anti arrythmitic drugs – cycle length
varibility.

Causes of wide QRS TACHYCARDIA
VT MACROREENTRANT VT
FOCAL VT
SVT WITH
ABERRANCY
FUNCTIONAL BBB
PREEXISTENT BBB
PREEXCITED SVT ANTIDROMIC AVRT
AT OR AVNRT WITH BYSTANDER
BYPASS TRACT
ANTIARRYTHMIC DRUGS CLASS 1A,CLASS 1C
AMIODARONE
ELECTROLYTE
ABNORMALITIES
HYPERKALEMIA

●
●
7. A
Vdissociation :
The most specific ECG finding for VT .
Cluesfor A
Vdissociation:
1. ClinicallybycannonAwaves, variableintensity ofS1, Variation
in SBPunrelated to respiration.
2. A
Vdissociation
3. A
Vratio of lessthan 1
4. 2:1 V
Ablock(d/t retrograde conduction)
5. V
ariation in QRSamplitude duringWCT
6. Fusion &capture beats,dissociatedpwaves

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