This document provides an overview of the approach to evaluating and classifying wide complex tachycardia. It defines wide complex tachycardia and discusses the main reasons for a widened QRS complex. The document outlines the initial approach to stable vs unstable patients and describes the key steps in analyzing the ECG which include assessing rate and rhythm, QRS axis, duration and morphology, as well as the relationship between atrial and ventricular activity. Important ECG criteria that favor ventricular tachycardia over supraventricular tachycardia are discussed.

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