2. Ventricular Tachycardia
• Arrhythmia of three or more consecutive complexes in
duration originating from the ventricles at a rate of
≥100 bpm
• Accounts for up to 80% of Wide complex tachycardia
• Nonsustained VT
– Three or more beats in duration, terminating
spontaneously in less than 30 s.
• Sustained VT
– VT greater than 30 s in duration and/or requiring
termination due to hemodynamic compromise in less than
30 s.
3. • Rate 100 to 250 / min
• Rhythm- Regular / slightly irregular
• QRS duration
– RBBB >140ms
– LBBB >160ms
• QRS Axis
– 20% of VTs have a northwest axis (sensitivity 20%,
specificity 96%)
– Right axis deviation with LBBB suggests VT(sensitivity
20%, specificity 97%)
– In patients with history of MI, axis deviation greater
than 40° from the baseline ECG
4. • QRS Concordance
– A concordant pattern is defined as predominant
QRS deflection, which is either all positive or all
negative across the precordial leads V1 to V6
– occurs in only 15% of VTs with specificity of >90%
– positive concordance seen in 18% of VTs with
RBBB-type pattern
– 12% of LBBB-type VTs showed negative
concordance
5.
6.
7. • AV dissociation
– Complete AV dissociation - 20% to 50%
– 1:1 VA relation - 30%
– 2:1 retrograde (VA) conduction and retrograde
Wenckebach block - 15%–20%
– sensitivity of 20%–50%, with specificity
approaching 100%
8. Capture and Fusion QRS Complexes
• A capture complex occurs when a
supraventricular impulse propagates through the
normal HPS system between VT QRS complexes
and excites both ventricles completely
• Capture complexes are narrow QRS complexes
similar to sinus complexes
• Fused QRS complexes are those in which the QRS
is a combination of 2 sources of ventricular
activation (supraventricular and ventricular
during VT)
9.
10. QRS mprphology
• In Precordial leads
– Concordant
– No R/S pattern
– Onset of R to nadir longer than 100 msec
• RBBB pattern
– qR, Rs or Rr´ in V1
– broad R (>40 ms) in lead V1
– rS complex in lead V6
• LBBB pattern
– r in V1 longer than 30 msec
– R to nadir of S in V1 greater than 60 msec
– Notching in the downstroke of the S wave
– qR or qS in V6
• Other specific patterns in V1
– Rs and W configuration in V1
19. Idiopathic Ventricular Tachycardia
• Refers to VT of unknown cause that occurs in
the absence of structural heart disease or
transient or reversible arrhythmogenic factors
(e.g., electrolyte disorders, myocardial
ischemia).
• Based on the location of the VT
– Outflow tract tachycardia
– Annular VT
– Fascicular VT (left septal VT)
20. Outflow Tract Tachycardia
• Accounts for 50% of idiopathic VT and 10% of
all VTs
• Types
– RVOT VT (80%)
– LVOT VT (20%)
• Occurs in young to middle age patients
• Mechanism – cAMP mediated delayed
afterdepolarizations
21. • RVOT VT
– LBBB pattern + Inferior axis
– R wave transition at or later than V3
• LVOT VT – 2 patterns on ECG
– RBBB pattern + Inferior axis ( aortomitral continuity)
– LBBB pattern + Inferior axis + R wave transition V2 (basal
aspect of superior LV septum)
• The prognosis for most patients RV/LV OT VT is good.
• Vagal maneuvers, Beta blockers, verapamil & adenosine
can terminate the VT
• exercise, stress,caffeine, isoproterenol infusion, and rapid
or premature stimulation often initiate or perpetuate the
tachycardia.
22. RVOT VT
LBBB pattern and Inferior axis in frontal plane
The precordial R wave transition occurs at or later than V3
23.
24. LVOT VT
LBBB pattern + Inferior axis - R wave transition occuring in V1
to V2 - prominent R wave is seen in lead I
25. Annular Ventricular Tachycardia
• VTs arising from the mitral or tricuspid
annulus
• Accounts for 4% and 7% of cases of idiopathic
VT
• Mitral annular VT
– RBBB
– S wave in V6
– monophasic R or Rs in leads V2 through V6
27. • Tricuspid Annular VT – foci generally arises
from the septal region
– LBBB morphology in V1
– Early transition in precordial leads (V3)
– Relatively narrower QRS complex
• Annular VTs behave similarly to outflow tract
VT, both in prognosis and in drug response
28. Fasicular VT(Left Septal VT)
• Accounts for 7-12% of idiopathic VT
• Also called as verapamil sensitive tachycardia
• Presents in young adulthood with slight male
preponderance
• Mechanism – macroreentry using the left
posterior (or less commonly anterior) fascicle
and abnormal purkinje or adjacent ventricular
myocardium
• Prognosis is generally good
33. Torsades de Pointes
• Refers to a VT characterized by QRS complexes of
changing amplitude that appear to twist around
the isoelectric line and occur at rates of 200 to
250/min
• characterized by prolonged ventricular
repolarization with QT intervals generally
exceeding 500 milliseconds
• VT that is similar morphologically to torsades de
pointes and occurs in patients without QT
prolongation, should generally be classified as
polymorphic VT, not as torsades de pointes
35. Accelerated Idioventricular Rhythm
• Enhanced ectopic ventricular rhythm with at least
3 consecutive ventricular beats, which is faster
than normal intrinsic ventricular escape rhythm
but slower than ventricular tachycardia
• Ventricular rate between 50 and 100 bpm
• Causes
– acute myocardial infarction shortly after successful
reperfusion
– digitalis toxicity
• Does not affect prognosis in acute MI
• No treatment required
37. Ventricular Flutter
• Sine wave pattern – large regular oscillations
without clear cut definitions of QRS complex
and T waves ocurring at a rate of 150-300/min
• Difficult to distinguish between rapid VT &
V.flutter
38. Ventricular fibrillation
• Recognized by the presence of irregular
undulations of varying contour and amplitude
occuring at a rate of 400-600/min
• Distinct QRS complexes, ST segments, and T
waves are absent.