CARDIOLOGY: Analyzing ECG Strips

PrefaceIn order to do an accurate analysis of a 12 lead ECG, one must have a systematic method of analysis. You
can develop your own technique but as a novice it is recommended to follow a proven method.
This manual contains ECGs with different rhythms and abnormalities. Analyze each one of them using the
recommended method of analysis below. Completing all the ECGs will help you to familiarize with the
ECGs you will encounter in your practice. The ECGs are labeled accordingly; it is now up to you to
complete the analysis.
While the method outlined below may seem extensive, with constant practice you will develop speed. Dr.
Hein J. J. Wellens, a well-known Electrophysiologist once said an “ECG unlocks the mystery of the heart.”
It is recommended by mentors in the field that, when analyzing an ECG you “look, think, and talk”.
Recommended Method of Analysis:
Step 1: Look at the rhythm strip.
1. Take note of what lead is used for the rhythms strip. Lead II and V1 are commonly used because P
waves are clearly seen on these leads. However, you are not limited to these two leads to search
for P waves as there are also other leads.
2. On the rhythm strip, identify the rhythm (sinus, atrial, junctional, or ventricular) then ask yourself
the following questions:
a. Are there P waves for every QRS?
b. Is the rhythm regular or irregular?
c. Are there any premature beats?
3. Next calculate the rate and look at the width of the QRS. Narrow QRS are of supraventricular
origin, whereas wide QRS of 120 msec are of ventricular origin.
4. Observe the morphology of the P waves. Pointed, tall P waves of 2.5 mm suggest RAE. “M” shaped
wide P waves of 120 msec suggest LAE.
5. On the rhythm strip you may also identify conduction disturbances such AV blocks (1°, 2°, Mobitz 1
or Mobitz 2 or 3° AVB)
6. As you can see, there are numerous things that can be observed on the rhythm strip.
Step 2: Look at the limb leads.
1. Ask yourself if there are blocks, hypertrophies, ischemia, MI, or miscellaneous changes (e.g.,
hyperkalemia).
2. Calculate the axis. From the axis, you may be able to identify hemiblocks.
3. Look at the partner leads (eg., Lead I and AVL). Are there abnormalities on the high lateral leads?
4. Look at the inferior leads. Are there abnormalities on the inferior leads?
5. Look at AVR. Positive AVR may indicate cross-leads (LA & RA), dextrocardia or right or extreme
right axis deviation. Observe the PR segment. Upsloping PR segment in AVR with downsloping PR
segment in other leads may suggest pericarditis.
6. Whatever you have observed in the limb leads, put it aside for the moment.
Step 3: Look at the chest leads.
1.
2.
3.
4.
Ask yourself if there are any blocks, hypertrophies, ischemia, MI or miscellaneous.
Observe the R wave progression.
Look at the partner leads – Leads V1 and V2. Observe for RVH, RBBB, septal ischemia or septal MI.
Next look at V3 and V4 and observe for anterior ischemia or MI.
5. Next look at leads V5 and V6 and observe for LVH, LBBB, lateral ischemia or MI.
Step 4: As your final analysis, put together all your observations from the limb and chest leads.
ECG Analysis Assignment Instructions
Use the ECG Package to review the ECG strips 1–100 and use the electronic ECG Analysis Worksheets
below to record your analysis of the strips. Each week submit the ECG Analysis Worksheets with your
completed analyses for the week (refer to your Course Outline for due dates).
Week 1 Strips 1–12 Sinus rhythms, ECG technical errors
Week 1: 12 ECGs
Sinus rhythms, ECG technical errors (enter the values here for each strips)
Strip #1
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #2
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #3
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #4
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #5
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #6
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #7
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #8
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #9
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #10
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #11
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Strip #12
Rate:
Axis:
PRI:
Rhythm
(reg or irreg):
QRSD:
Interpretation:
Hexaxial reference system for estimating the AXIS value.
For calculating the Heart rate: you can use the Little Block Method, Bog Block method, Triplicate method or 6 second
method.
Note: for PR interval (PRI) – This measurement should be 0.12-0.20 seconds, or 3-5 small squares in duration.
QRS duration (QRSD) – The normal duration (interval) of the QRS complex is between 0.08 and 0.10
seconds
Note: per my professor, for this assignment, we are only dealing with sinus rhythm. So I assumed the
interpretations should be all Sinus Rhythm??