Welch Allyn Means ECG Physicians Manual for CP Series Electrocardiographs - User Manual - Manual (Page 12)

MEANS Physicians Manual
Welch Allyn
12
2.5 Right Bundle Branch Block (RBBB)
The ECG abnormality in RBBB consists of a late, protracted QRS activity to the right and
anterior with concomitant overall increase of QRS duration (

130 ms). The program therefore
looks for a late R, an R

or a broad notched R wave in V1 or V2, all with delayed intrinsicoid
deflection, and reciprocal broad S waves in the lateral leads.
The QRS axis has a certain influence on the S duration in lead I. Lead I, although horizontal
in geometrical space, is tilted upward on the left side in electrical space. In left axis deviation,
this will result in a projected S wave which is less deep and of shorter duration than the S
wave in V5 or V6 leads that are tilted downwards on the left. This aspect has been taken into
account for the criteria on the S duration. In the presence of RBBB, a diagnosis of RVH may
also be entertained if the R wave in V1 is tall.
Skip tests
if:
QRS duration < 130 ms
or S

amplitude in V1

100 µV
Say:
“RBBB”
if: S duration  50 ms in I, V5, V6
and intrinsicoid deflection at

55 ms in V1 or V2
or S duration

30 ms in V5 or V6
and S duration in I

20 ms and QRS axis <

45

or S duration in I

30 ms and QRS axis

45

and R

wave or R notch in V1 or V2
or Q wave and intrinsicoid deflection at

50 ms in V1
if:
test RBBB passed
and Q amplitude > 100 µV in V1 and V2
then:
Say: “septal infarct”
if: Q duration

30 ms in V1 or V2
Say: “probable septal infarct”
if: Q duration

20 ms in V1 or V2
S
uppress “RBBB”
if: Q amplitude in V2  100 µV
or R amplitude in V2 < 200 µV
or intrinsicoid deflection in V2 at < 50 ms
if:
test RBBB passed
then:
Say:
“posterior infarct”
if: positive QRS amplitude in V1  1500 µV
and positive T amplitude in V1

700 µV