Welch Allyn Means ECG Physicians Manual for CP Series Electrocardiographs - User Manual - Manual (Page 14)

MEANS Physicians Manual
Welch Allyn
14
2.8 Atrial overload
The diagnosis of right or left atrial overload (RAO and LAO) will be considered in the
presence of a normal P axis. Otherwise an unusual P axis will be reported.
In LAO the P wave is characterized by a broad negative terminal part in lead V1 and an
increase of overall duration. In RAO a tall P wave in lead II and aVF and/or in V1 and V2 is
expected. In diagnosing RAO an adjustment has been built in for heart rate: in tachycardia the
amplitude of the P wave has to be slightly higher to qualify for the diagnosis, than with normal
heart rate. The reason for this adjustment is the superposition of the P on the preceding U
wave or T wave occurring at higher heart rates. Above 130 BPM no attempt is made to
diagnose RAO.
Skip tests
if:
P axis
 
30

or P axis > 100

Say:
“left atrial overload”
if: negative P amplitude in V1

180 µV
and P duration > 135 ms
or LVH test passed
Say:
“right atrial overload”
if: heart rate < 100 BPM
and positive P amplitude

275 µV in V1 or V2
or positive P amplitude in II + positive P amplitude in aVF

525 µV
or 100

heart rate < 130 BPM
and positive P amplitude

300 µV in V1 or V2
or positive P amplitude in II + positive P amplitude in aVF  575 µV
2.9 Atrial abnormalities
Say: “unusual P axis”
if: P axis
 
30

or P axis > 100

Say:
“intra-atrial conduction delay”
if: P duration > 135 ms
and negative P amplitude in V1

180 µV
Say:
“high P voltage”
if: test RAO did not pass
and positive P amplitude

275 µV in any lead
and heart rate < 100 BPM
or positive P amplitude

300 µV in any lead
and 100

heart rate < 130 BPM