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SECTION II: Abnormal Wave Morphology
ELECTROCARDIOGRAPHIC DIAGNOSIS OF VENTRICULAR
PREEXCITATION
Typically, with ventricular preexcitation, the PR interval is 0.12 second in duration
and the QRS complex is 0.10 second. Ventricular preexcitation produces a prolonged
upstroke of the QRS complex, which has been termed a “delta wave.” Positive delta (V1
to V5, I and aVL) and negative delta (II, III, and aVF) waves are illustrated in Figure 7.6.
A
I
aVR
V1
V4
II
aVL
V2
V5
III
aVF
V3
V6
B
I
aVR
V1
V4
II
aVL
V2
V5
III
aVF
V3
V6
F I G U R E 7 . 6 .
Positive and negative delta waves (
arrows
) in two patients.
