Rhythm diagnosis in regular wide complex tachycardia

V-Tach vs. SVT

Factor	V Tach	SVT w/ Aberrancy
Age	>50	<35
History	MI, CHF, CABG, MVR	MVR, WPW
Cannon A Waves	Present	Absent
Arterial Pulse	Variation	No variation
First heart sound	Variable	Not variable
Fusion Beats	Present	Absent
AV dissociation	Present	Absent
QRS	>0.14sec	<0.14sec
Axis	Extreme LAD (< -30)	Normal or slightly abnl
Vagal Maneuvers	No response	Slows or terminates
QRS morphology (RBBB-like pattern)	V1 - R or qR V6 - rS	V1 - rsR' V6 - R(slurredS)
QRS morphology (LBBB-like pattern)	V1 or V2 - Broad R wave (>40msec) V6 - Any Q or QS	V1 - rS or QS V6 - qRs

Algorithms

• Only for regular rhythms
• Only for treatment decision if pt is stable
• Assume V-tach until proven otherwise

Brugada Algorithm

1. Absence of an RS complex in all precordial leads?
   1. If yes then VT
   2. If no then continue
2. RS interval >100ms in any precordial lead? (onset of R wave to deepest part of S wave)
   1. If yes then VT
   2. If no then continue
3. AV dissociation?
   1. If yes then VT
   2. If no then continue
4. Morphology criteria for v-tach present in both V1-2 and V6?
   1. If yes then VT
   2. If no then possibly SVT w/ aberrant conduction

aVR Algorithm

• In lead aVR:

1. Presence of an initial R wave?
   1. If yes then VT
   2. If no then continue
2. Presence of an initial r or q wave >40ms
   1. If yes then VT
   2. If no then continue
3. Presence of a notch on descending limb of a negative onset, predominantly negative QRS?
   1. If yes then VT
   2. If no then continue
4. Ventricular activation-velocity ratio (Vi/Vt) ≤1?
   1. If yes then VT
   2. If no then SVT

Niemann Algorithm

• Combination of the most specific aspects of the above two algorithms

1. Presence of an initial R wave in aVR?
   1. If yes then VT
   2. If no then continue
2. Is there concordance (monophasic with same polarity) in all of the precordial leads?
   1. If yes then VT
   2. If no then continue
3. Is there evidence of AV dissociation?
   1. If yes then VT
   2. If no then continue
4. Is the QRS morphology in V1 and V6 consistent with either LBBB or RBBB?
   1. If no then VT
   2. If yes then SVT with aberrancy

See Also

• Tachycardia (Wide)
• SVT
• ACLS (Main)
• ACLS: Tachycardia
• PALS (Main)

Source

• Brugada et al. A new approach to the differential diagnosis of a regular tachycardia with a wide QRS Complex. Circulation, Vol 83, 1991.
• Vereckei et al. New algorith using only lead aVR for differential diagnosis of wide QRS complex tachycardia
• Niemann. Harbor-UCLA Grand Rounds