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 - Rs
QRS morphology (LBBB-like pattern)	V1 or V2 - Broad R wave (>40msec) V6 - Any Q or QS	V1/V2 - Small R V6 - no Q

Brugada Algorithm

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

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 one 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 and predominantly neg 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

See Also

Tachycardia (Wide)

Source

• Brugada et al. A new approach to the differential diagnosis of a regular tachycardia with a wide QRS Complex. Circulation, Vol 83, 1991.