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Interpreting an EKG rhythm strip: An 8 step
method
You can master the interpretion of an ECG rhythm strip through
practice. Bydeveloping a consistent approach you will be sure to
include all the pertinent data inyour analysis. This 8-step method
will help you
n ECG waveform has three basic elements! the " wave# the $%&
comple'# and the
T wave. These elements can be further divided into a "%
internal# ( wave# &Tsegment# and $T interval.
Step IEvaluate the P wave. The P wave represents the
depolarization of the atria.(Depolarization occurs as the impulse
passes through the muscle tissue.) )bservethe " wave*s si+e# shape#
and location in the waveform. ,f the " wave consistentlyprecedes
the $%& comple'# the & sino-atrial node is initiating the
electrical
impulse.
Step IIEvaluate the atrial rhythm The " wave should occur at
regular intervals# with onlysmall variations associated with
respiration. (sing calipers# you can easily measurethe interval
between " waves# or the "-" interval. Compare the "-"
intervals.
Step IIIDetermine the atrial rate /or a 0uic1 count# add the
number of " waves in two
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2-second segments and multiply by 34. To be more accurate# count
the smalls0uares between the ape'es of two " waves. Each small
s0uare e0uals 4.45
second6 3#744 s0uares e0ual 3 minute. ivide 3#744 by the number
of s0uares youcounted to get the atrial rate.
4Calculate the duration of the PR interval.
Count the small s0uares between the beginning of the " wave and
the be-
ginning of the $%& comple'. 9ultiply that number by 4.45
second. The normal inter-val is between 4.3: and 4.:4 second# or
between three and five small s0uares wide.,f the interval is wider#
there is a delay in conduction of the impulse to the
ventricles.
7 Evaluate the ventricular J rhthm
(se calipers to measure the %-% intervals. "lace the calipers on
the same pointof the $%& comple'. ,f the %-% intervals remain
consistent# the ventricular rhythm isregular.
6 eterminethe ventricular rate; (se the same formula for
calculating the atrial rate &tep 2# but count the smalls0uares
between the two % waves. lso chec1 that the $%& comple' is!
shapedappropriately for the lead you*re monitoring.
< Calculate the duration of the !R" comple#
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Count the s0uares between the beginning and the end of the
$%& comple' andmultiply by 4.45 second. normal $%& comple'
is less than 4.3: second. &ome
references specify 4.4= to 4.34 second as the normal duration
for the $%& comple'.
$ Calculate the duration of the !T interval
Count the number of s0uares from the beginning of the $%&
comple' to the end ofthe T wave. 9ultiply this number by 4.45
second. The normal range is 4.2= to 4.55second# or > to 33 small
s0uares wide.
