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ECG Lectures
Wide Complex Tachycardias
Selim Krim, MD
Assistant Professor
Texas Tech University Health Sciences Center
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
Differential Diagnosis of Wide
QRS Tachycardias
Ventricular Tachycardia
Supraventricular Tachycardia with BBB or WPW
Atrial fibrillation with aberration or with WPW
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.
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!
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.
Monomorphic Ventricular Tachycardia
Torsades de Pointes
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.
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
Ventricular Tachycardia
Ventricular Tachycardia
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 Swave 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
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!
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)!
R waves with a notch or slur on the
downstroke of the R waves
Monophasic R wave with a notch or slur on
the upstroke of R wave: 50-50 possibility or
either!
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!
Atrial Fibrillation With WPW
Atrial Fibrillation
V-tach or SVT with BBB?
Diagnosis?
Let’s practice!
ECG 1
ECG 2
ECG 3
ECG 4
ECG 5
ECG 6
ECG 7
ECG 8
ECG 9
Brugada Criteria
Questions ?
Thank you