CHARACTERISTICS OF
WIDE-COMPLEX TACHYCARDIA CHART

CHARACTERISTIC	VENTRICULAR TACHYCARDIA	RATE-RELATED ABERRANCY	PREEXCITATION TACHYCARDIA
AV dissociation (more QRS than P waves	Rules in	Practically rules out	Practically rules out
Captured beats	Rules in	Rules out	Rules out
Fusion Beats	Rules in	Rules out	Rules out
Rhythm (ventricular)	Regular, except Torsades de points	Regular, except AF & MAT	Regular, except AF & MAT
QRS axis	Leftward shift supports diagnosis	Usually normal	Usually normal
QRS duration >140 msec	Strongly supports diagnosis	Almost never occurs	Rare
Remote myocardial infarction	Common	Usually not present	Usually not present
Normal heart	Uncommon	Common	Common
Response to carotid massage	None	May terminate if AV node-dependent	May terminate if AV node-dependent
Response to Valsalva maneuver	None	May terminate if AV node-dependent	May terminate if AV node-dependent

MORPHOLOGY CRITERIA FEATURES FAVORING VT
1. RBBB pattern: Monophasic R or biphasic qR, QR, or RS in V1, S>R or QS in V6
2. LBBB pattern: Broad R or wide R-S length (>30msec)in V1 or V2.
Notched downstroke of S wave in V1 or V2.
>60msec to nadir of S in V1 or V2. qR or QS pattern in V6

FEATURES FAVORING ABERRANT SVT
1. RBBB PATTERN: Triphasic rSR in V1, Triphasic rSR in V6, R>S in V6
2. LBBB PATTERN: No R in V1, Small narrow R in V2, No Slurring of S wave downstroke,
Monophasic R in V6, Presence of septal Q in I & V6

MAIN PAGE