AN APPROACH TO WIDE QRS TACHYCARDIA

1. AN APPROACH
TO WIDE
COMPLEX
TACHYCARDIA
PRESENTOR : Dr NIHANTH REDDY V
MODERATOR : Dr KUMAR NARAYANAN

2. DEFINITION
Wide QRS Tachycardia is defined by a ventricular rate > 100/min and
QRS width > 120 milliseconds

3. CLASSIFICATION

4. WHY IS THERE A WIDENED
QRS ?
A widened QRS complex occurs
when ventricular contraction is
abnormally slow for one of the
following reasons :
1. The arrhythmia originates
outside of the normal
conduction system and
below the AV node -
Ventricular tachycardia

5. 2. Abnormalities within the His
Purkinje system – SVT with
aberrancy

6. 3. Pre excitation with an SVT
conducting antegrade over an
accessory pathway, resulting in
direct activation of ventricular
myocardium

7. • Atrial
fibrillation/flutter/tachycardia
with aberrant conduction or
antegrade conduction via an
accessory pathway

8. • Polymorphic VT
• Ventricular fibrillation

9. APPROACH TO WIDE COMPLEX TACHYCARDIA
• INITIAL APPROACH :
1. Assessment of hemodynamic status :
Unstable - Cardioversion irrespective of the mechanism of arrhythmia
Stable – In a stable patient, a focused clinical evaluation should include
the following :
History
Physical examination
Ancillary testing
Diagnostic maneuvers in selected patients

10. CLINICAL CLUES TO WIDE COMPLEX
TACHCYARDIA
VENTRICULAR TACHYCARDIA SVT
Age > 35 – 85 % Age< 35 years – 70 %
Old MI
Structural heart disease – 90 %
Signs of acute or chronic HF
Presence of ICD
Atrial arrhythmias with regular WCT
Structurally normal heart
A healed sternal incision as evidence of previous
cardiac surgery
A sequalae of peripheral artery disease or stroke
Family H/O SCD
Drugs – IC, III, LQTC Pre existing BBB/WPW
Electrolytes

11. DICTUM
• When the diagnosis of SVT remains uncertain, it is recommended that
the patient be treated as if the rhythm is VT until definitely proven
otherwise
• Unstable patients should be presumed to have VT and treated as such

12. APPROACH TO WIDE COMPLEX TACHYCARDIA
• When analyzing an ECG with a wide QRS complex, a systematic
approach is advised
• If available, comparison with a baseline ECG tracing in sinus rhythm or
atrial fibrillation is helpful
• Helpful clues on a baseline ECG may include fascicular and/or bundle
branch block, signs of prior infarction, or ventricular pre-excitation

13. • The following steps are recommended
1. Assessment of rate
2. Assessment of rhythm – regular or irregular ?
3. What is the QRS axis, duration ?
4. Presence and pattern of atrial activity (p wave ) should be identified
5. Relationship between atrial and ventricular activity should be
determined
6. Wide QRS morphology should be evaluated

14. • What is the rate ?
• Is the rhythm regular or irregular ?
 The rate of the WCT is of limited use in distinguishing VT from SVT
VT is generally regular. Slight variation in RR intervals is sometimes
seen and suggests VT as opposed to most SVTS, which are
characterized by uniformity of RR intervals
Warm up phenomenon – suggests VT
Marked irregularity of RR intervals occurs in polymorphic VT and in
AF aberrant conduction

15. WARM UP PHENOMENON
• If the start of tachycardia is recorded, it
is valuable to assess the initial RR
beats.
• If the RR intervals during the start of
tachycardia is irregular – it suggests VT
• This phenomenon is referred to as
warm up phenomenon and is
characteristic of VT

16. WHAT IS THE QRS AXIS,
DURATION AND
MORPHOLOGY ?
• QRS axis : Extreme right axis deviation
strongly favors VT
• Compared with the axis during sinus
rhythm of the old ECG, an axis shift during
the WCT of more than 40 degrees
suggests VT
• In patients with an RBBB like WCT, a QRS
axis to the left of -30 degrees suggests a
VT
• In patients with an LBBB like WCT, a QRS
axis to the right of +90 degrees suggests a
VT

17. • QRS duration : By definition,
the QRS duration is at least
120 milli seconds in a WCT
• In general, a wider QRS > 160
milliseconds favors VT
• In an RBBB-like WCT, a QRS
duration > 140 milliseconds
suggests VT
• In an LBBB-like WCT, a QRS
duration > 160 milliseconds
suggests VT

18. • CONCORDANCE : Concordance is present
when QRS complexes in all precordial leads
are monophasic with same polarity
• When present, concordance is frequently
associated with VT
• Positive concordance : V1-V6 entirely
positive with tall monophasic R waves
• Negative concordance : V1-V6 entirely
negative with deep monophasic QS
complexes – strongly suggestive of VT

19. • Three additional findings suggestive for a ventricular origin
tachycardia include :
1. VPC’s during SR with the same QRS configuration as during VT
2. QRS width during tachycardia less than QRS width during SR
3. A bundle branch like configuration during VT which is different from
the bundle branch block pattern during SR

20. • AV DISSOCIATION : When identified on ECG,
the presence of AV dissociation largely
establishes VT as the diagnosis
• AV is dissociation is characterized by atrial
activity that is independent of ventricular
activity, with ventricular rate exceeding the
atrial rate

21. • FUSION AND CAPTURE BEATS : Fusion and/or capture beats, when
identified on the surface ECG in a patient with WCT, are diagnostic for VT
• Fusion beats : Occur when one impulse originating from the ventricle and a
second supraventricular impulse simultaneously activate the ventricular
myocardium. The resulting QRS complex has a morphology intermediate
between that of a sinus beat and a purely ventricular complex
• Capture beats/Dressler beats : QRS complexes during a WCT that are
identical to the sinus QRS complex. It implies that the normal conduction
system has momentarily captured control of ventricular activation from the
VT focus
• Fusion and capture beats are noticed when the tachycardia rate is slower

24. QRS MORPHOLOGY

25. ECG
CRITERIA
FAVORING
VT THAN SVT

26. • There is no single criterion or combination of criteria that provides
complete diagnostic accuracy in evaluating a WCT
• It is therefore necessary to integrate multiple ECG findings into a
diagnostic strategy
• Of the several strategies proposed, the Brugada criteria is the most
widely used

28. VERECKI
ALGORITHM

29. WIDE QRS TACHYCARDIA WITH IRREGULAR
RHYTHM
• Atrial fibrillation or flutter with variable AV conduction
1. Bundle branch block
2. Accessory pathway
• Torsade's de pointes

36. THANK YOU