1. Texas Tech University Health Sciences Center
ECG Lectures Wide Complex Tachycardias
Selim Krim, MD
Assistant Professor
Texas Tech University Health Sciences Center

2. Objectives
Understand the importance and clinical consequence of making the right diagnosis of wide complex tachycardia
Get familiar with the different etiologies of wide complex tachycardia
Step wise approach to diagnosing wide complex tachycardia
Recognize SVT with aberrancy from ventricular Tachycardia

3. Differential Diagnosis of Wide QRS Tachycardias
Ventricular Tachycardia
Supraventricular Tachycardia with BBB or WPW
Atrial fibrillation with aberration or with WPW

4. Clinical pearls
One of the most common lethal errors made in arrhythmia diagnosis is to mistake VT for SVT and treat with verapamil, diltiazem, and adenosine, all of which can precipitate ventricular fibrillation in patients in VT, even if initially stable.
Therefore, all wide-complex tachycardias should be assumed to be VT until proven otherwise.

5. Bedside Clues to V-Tach
Advanced heart disease (e.g., coronary heart disease) statistically favors ventricular tachycardia
Cannon 'a' waves in the jugular venous pulse suggests ventricular tachycardia with AV dissociation. Under these circumstances atrial contractions may occur when the tricuspid valve is still closed which leads to the giant retrograde pulsations seen in the JV pulse. With AV dissociation these giant a-waves occur irregularly.
If the patient is hemodynamically unstable, think ventricular tachycardia and act accordingly!

6. Ventricular Tachycardia
A run of three (3) or more consecutive PVCs
Sustained (lasting >30 sec) vs. nonsustained
Monomorphic (uniform morphology) vs. polymorphic vs. Torsade-de-pointes  
Torsade-de-pointes: a polymorphic ventricular tachycardia associated with the long-QT syndromes characterized by phasic variations in the polarity of the QRS complexes around the baseline.  

7. Monomorphic Ventricular Tachycardia

8. Torsades de Pointes

9. ECG Clues to Ventricular Tachycardia
Regularity of the rhythm: If the wide QRS tachycardia is sustained and monomorphic, then the rhythm is usually regular (i.e., RR intervals equal)
A-V Dissociation strongly suggests ventricular tachycardia! Unfortunately AV dissociation only occurs in approximately 50% of ventricular tachycardias .
Fusion beats or captures often occur when there is AV dissociation and this also strongly suggests a ventricular origin for the wide QRS tachycardia.

10. ECG Clues for V Tach
Bizarre frontal-plane QRS axis (i.e. from +150 degrees to -90 degrees or NW quadrant) suggests ventricular tachycardia
QRS morphology similar to previously seen PVCs suggests ventricular tachycardia
If all the QRS complexes from V1 to V6 are in the same direction (positive or negative), ventricular tachycardia is likely  
Especially wide QRS complexes (>0.16s) suggests ventricular tachycardia

11. Ventricular Tachycardia

12. Ventricular Tachycardia

14. V-Tach vs. SVT with Aberrancy
Features favoring VT:
RBBB Pattern
Monophasic R or biphasic qR, QR, or RS in V1
S > R or QS in V6  
LBBB pattern
Broad R wave or wide R-S length (> 30msec) in V1 or V2
Notched downstroke of S-wave in V1 or V2
qR or QS pattern in V6  
Features favoring SVT:
RBBB pattern
Triphasic rSR' in V1
Triphasic rSR' in V6
R > S in V6
LBBB pattern
No R in V1
No slurring of S-wave downstroke
Monophasic R in V6
Presence of septal Q in I & V6

15. Aberrancy vs. Ectopy
If the QRS in V1 is mostly positive the following possibilities exist:  rsR' or rSR' QRS morphologies suggests RBBB aberrancy >90% of the time!

16. Aberrancy vs. Ectopy
Monophasic R waves or R waves with a notch or slur on the downstroke of the R waves suggests ventricular ectopy > 90% of the time (see below)!

17. R waves with a notch or slur on the downstroke of the R waves

18. Monophasic R wave with a notch or slur on the upstroke of R wave: 50-50 possibility or either!

19. Four-step Algorithm to Wide Complex Tachycardia
Step 1: Absence of RS complex in all leads V1-V6? Yes: Dx is ventricular tachycardia!
Step 2: No: Is interval from beginning of R wave to nadir of S wave >0.1s in any RS lead? Yes: Dx is ventricular tachycardia!
Step 3: No: Are AV dissociation, fusions, or captures seen? Yes: Dx is ventricular tachycardia!
Step 4: No: Are there morphology criteria for VT present both in leads V1 and V6? Yes: Dx is ventricular tachycardia!
NO: Diagnosis is supraventricular tachycardia with aberration!

20. Atrial Fibrillation With WPW

21. Atrial Fibrillation

22. V-tach or SVT with BBB?

23. Diagnosis?

24. Let’s practice!

25. ECG 1

26. ECG 2

27. ECG 3

28. ECG 4

29. ECG 5

30. ECG 6

31. ECG 7

32. ECG 8

33. ECG 9

35. Brugada Criteria

36. Questions ?

37. Thank you