Download Week 2 Work Sheet - Cardiaceducation1

Week 2 Work Sheet
Our main objective is to rapidly determine the heart rate from the EKG
Find a specific R wave that peaks on a heavy black line (our "start" line).
Next: Count off "300, 150, 100" for every thick line that follows the start line,
naming each line as shown. Know these numbers; you will use them throughout
your career.
Then: Count off the next three lines after "300, 150, 100" as "75, 60, 50."
From Rapid Interpretation of EKG's copyright © 2011 COVER Publishing Co. Inc.
Where the next R wave falls, determines the rate. It's that simple!
On EKG the QRS complex represents ventricular contraction. The Q wave is the
first downward wave of the QRS complex, and it is followed by an upward R
wave, however the Q wave is often absent on EKG. Necrosis (death) of an area
of the heart muscle produces a Q wave on EKG.
The Q wave, when present, always occurs at the
complex and is the first downward deflection of the complex.
of the QRS
The downward Q wave is followed by an upward
wave.
NOTE: If there is any upward deflection in a QRS complex that appears before a
"Q" wave, it is not a Q wave, for by convention, when present, the Q wave is
always the first wave in the complex.
The Q wave makes the diagnosis of infarction.
The diagnosis of myocardial infarction is usually based on the presence of
significant
waves that are produced by the area of necrosis.
NOTE: The Q wave is the first downward stroke of the QRS complex, and it is
never preceded by anything in the complex. In the QRS complex, if there is any
positive wave - even a tiny spike - before the downward wave, the downward
wave is an S wave (and the upward wave preceding it is an R wave).
Significant Q
are absent in normal tracings.
We use a capital "Q" to designate a significant Q wave,
however small "q" waves are not significant.
From Rapid Interpretation of EKG's copyright © 2011 COVER Publishing Co. Inc.
If there are Q waves in lead I and lead AVL, there is a lateral infarction.
Please take a moment and glance at page 46 to make a mental note of the leads
that have a positive electrode located laterally on the left arm.
A lateral infarction involves the lateral portion of the
When a lateral infarction occurs,
ventricle.
waves appear in leads I and AVL.
NOTE: One might abbreviate Lateral Infarction as L.I. Just remember AVL for
"Lateral" and "I" for Infarction (after all, Roman Numeral "I" for lead I is just a
capital "i"). It's an easy way to recall the leads that demonstrate lateral infarction.
From Rapid Interpretation of EKG's copyright © 2011 COVER Publishing Co. Inc.
Inferior ("diaphragmatic") infarction is diagnosed by the presence of Q waves in
II, III, and AVF.
The inferior wall of the heart rests upon the diaphragm, so the term
"diaphragmatic" infarction is sometimes used to indicate an infarction in
the inferior portion of the left
An
AVF.
.
infarction is identified by significant Q waves in leads II, III, and
NOTE: If I told you the way that I remember the leads for inferior infarction, this
book would be banned. You may want to make your own memory tool for
remembering the leads for Inferior ("diaphragmatic") Infarction using "two, three,
and F."
From Rapid Interpretation of EKG's copyright © 2011 COVER Publishing Co. Inc.
Q waves in chest leads V1, V2, V3, or V4 signify an anterior infarction.
NOTE: The chest leads are mainly placed anteriorly on the chest, so this is a
good way to remember the leads for anterior infarction.
The presence of Q waves in V1, V2, V3, or V4 indicates an infarction in the
anterior wall of the
ventricle.
NOTE: Statistically, anterior infarctions are very deadly, but fortunately,
immediate treatment with intravenous thrombolytic medications or angioplasty
with stenting has improved the survival rate substantially.
From Rapid Interpretation of EKG's copyright © 2011 COVER Publishing Co. Inc.
It is common practice to determine the general location of an infarction, but with a
little anatomical knowledge of the heart's coronary blood supply*, we can make a
far more sophisticated diagnosis.
There are two coronary arteries that provide the heart with a continuous supply of
oxygenated
.
Quickly review the illustration.
The Left Coronary Artery has two major branches; they are the Circumflex
branch and the
Descending branch.
The Right Coronary Artery curves around the right
.
* The pulmonary artery has been "surgically" removed in this illustration to show
the origin of the coronary arteries at the base of the aorta.
From Rapid Interpretation of EKG's copyright © 2011 COVER Publishing Co. Inc.
A lateral infarction is caused by an occlusion of the Circumflex branch of the Left
Coronary Artery. An anterior infarction is due to an occlusion of the Anterior
Descending branch of the Left Coronary Artery.
The Circumflex branch of the Left Coronary Artery distributes
blood to the
portion of the left ventricle.
The Anterior Descending branch of the Left Coronary Artery
supplies blood to the anterior portion of the
ventricle.
The Circumflex and the Anterior Descending are the two main
branches of the
Coronary Artery.
From Rapid Interpretation of EKG's copyright © 2011 COVER Publishing Co. Inc.
The base of the left ventricle receives its blood supply from branches of either the
Right or the Left Coronary Artery, depending on which artery is "dominant."
Inferior ("diaphragmatic") infarctions are caused by an occluded
terminal branch of either the Right or the
Coronary Artery.
So the diagnosis of inferior infarction does not necessarily identify
the artery branch that is occluded, unless you have a previous
coronary angiogram (an x-ray highlighting the coronary arteries)
to identify which
artery supplies the inferior portion
of that patient's left ventricle.
NOTE: Left or Right Coronary "dominance" denotes which coronary artery is the
major source of blood supply to the base of the left ventricle. Right Coronary
dominance is by far most common in humans