Download Interesting ECGs

Interesting ECGs
Sarah Gutman
History of the ECG
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1876 Marey uses the electrometer to
record the electrical activity of an
exposed frog's heart.
1878 British physiologists John
Burden Sanderson and Frederick Page
record the heart's electrical current
with a capillary electrometer and
shows it consists of two phases
1891 British physiologists William
Bayliss and Edward Starling of
University College London improve
the capillary electrometer. They
connect the terminals to the right
hand and to the skin over the apex
beat and show a "triphasic variation
accompanying (or rather preceding)
each beat of the heart".
1893 Willem Einthoven introduces
the term 'electrocardiogram' at a
meeting of the Dutch Medical
Association.
History of the ECG
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In 1924 Einthoven was
awarded the Nobel prize
in Physiology or Medicine
for his discovery of the
mechanism of the
electrocardiogram.
60 year old woman with 3 hours of chest
pain
Acute Posterior MI
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ST depression in leads V1 - 3
tall R wave
tall upright T wave in leads V1 -3 usually associated
with inferior and/or lateral wall MI
80 year old with dizziness
Digoxin
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shortened QT interval
characteristic down-sloping ST depression
Possible Effects of Digoxin on the ECG
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Depression or sagging of the ST segment which is concave in an upward direction; it looks as if the ST segment alone has been pulled down. These
changes are more apparent in the lateral precordial leads, although they may also be seen in the limb leads.
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The T waves are often flattened and the QT interval (ST segment) shortened.
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Usually the PR interval is slightly prolonged as a result of an enhanced vagal effect upon the AV node.
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In some cases there are abnormalities of the U wave (prominent or inverted) which may be due to digitalis itself, or can be secondary to hypokalemia.
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Ventricular premature beats
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Atrial tachycardia (automatic, accelerated, or non-paroxysmal)
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Atrioventricular junctional tachycardia (automatic or non-paroxysmal)
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Accelerated junctional rhythm (automatic or non-paroxysmal)
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Accelerated idioventricular rhythm (automatic or non-paroxysmal)
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Ventricular tachycardia
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Bidirectional tachycardia (usually a junctional tachycardia with alternating right and left bundle branch block)
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Ventricular fibrillation
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Abnormal conduction due to digitalis toxicity includes the following:
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Sinus bradycardia
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Sinus pause or arrest
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Sinoatrial block
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First degree atrioventricular block
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Second degree atrioventricular block (Mobitz 1 or Mobitz 2)
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Third degree atrioventricular block
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Combined arrhythmia and conduction abnormalities due to digitalis toxicity include the following:
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Atrial tachycardia with atrioventricular junctional block (PAT with block)
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Sinus bradycardia associated with atrioventricular junctional tachycardia
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Accelerated junctional rhythm associated with underlying atrial fibrillation (atrial fibrillation with regularization)
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Atrial flutter, atrial fibrillation, and Mobitz type II second degree AV block are the least likely of all the possible abnormalities.
55 year old man – routine ECG in cardiology
outpatients
Heterotopic Heart Transplant
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two distinct QRS morphologies
two distinct rates
36 year old lady with recurrent blackouts
VT + AICD
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polymorphic ventricular tachycardia
large deflection (arrowed) is the defibrillator
discharging.
Following the defibrillation a dual chamber
pacemaker can be seen.
A 75 year old lady with loud first heart
sound and mid-diastolic murmur
AF + RVH
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AF
There is the suggestion of right ventricular
hypertrophy.:
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tall R waves in the right precordial leads (V1 and V2
deep S waves in the left precordial leads (V5 and V6);
a R:S ratio >1 in V1 and V2 is suggestive of RVH
right axis deviation and RV1 >7 mm.
The combination of Atrial Fibrillation and Right Axis
Deviation on the ECG suggests the possibility of
mitral stenosis.
A 75 year old lady with loud first heart
sound and mid-diastolic murmur
P Mitrale and RVH
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P mitrale or left atrial enlargement is manifest as broad
notched (M shaped) p wave in lead II, classically seen in
mitral stenosis.
The broad negative P wave in V1 is also indicative of left
atrial overload.
qR pattern in V1 with T wave inversions in anterior leads
is suggestive of right ventricular hypertrophy.
A 79 year old man with 5 hours of severe,
central, crushing chest pain
Acute myocardial infarction in the
presence of left bundle branch block
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The sequence of repolarization is altered in LBBB, with the ST
segment and T wave vectors being directed opposite to the QRS
complex.
These changes may mask the ST segment depression and T wave
inversion induced by ischemia.
On the other hand, the diagnosis of an acute MI or ischemia can
occasionally be made in a patient with underlying LBBB if certain STT changes are seen, particularly if the ST-T vectors are in the same
direction as the QRS complex as in the Sgarbossa criteria described
below.
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The presence of deep T wave inversions in leads with a predominantly
negative QRS complex (eg,V1-V3) is highly suggestive of evolving
ischemia or MI.
ST elevations in leads with a predominant R wave (as opposed to QS or
rS waves) are also strongly suggestive of acute ischemia.
Pseudonormalization of previously inverted T waves is suggestive but not
diagnostic of ischemia.
Attempts to Improve diagnosis of AMI in the
presence of LBBB
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Serial ECG changes — 67 percent sensitivity
ST segment elevation — 54 percent sensitivity
Abnormal Q waves — 31 percent sensitivity
Initial positivity in V1 with a Q wave in V6 — 20 percent
sensitivity but 100 percent specificity for anteroseptal MI
Cabrera's sign — 27 percent sensitivity overall, 47
percent for anteroseptal MI
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Cabrera's sign refers to prominent (0.05 sec) notching in the
ascending limb of the S wave in leads V3 and V4.
However, there may be a high degree of interobserver
variability in accurate identification and their sensitivity is quite
low.
78 year old woman with central chest pain
radiating to jaw
Second degree atrioventricular block: Mobitz
type I (Wenckebach block) + inferior STEMI
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progressive PR interval prolongation preceds a
nonconducted P wave
The site of block is in the AV node in most cases (70 to
75 percent), with the remaining cases involving the His
bundle, bundle branches, or fascicles
Mobitz type I block (due to ischemia of the AV node) is
not an uncommon complications of an inferior myocardial
infarction (given the RCA supplies the AV nose in over
90% of individuals).
80 year old woman in pre-admission clinic
for CABG and AVR in 2 weeks
Bifasicular block
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Abnormal left axis deviation
qR complex in the lateral limb
leads (I and aVL)
rS pattern in the inferior leads (II,
III, and aVF)
Bifascicular block refers to
conduction disturbances below
the atrioventricular (AV) node in
which the right bundle branch and
one of the two fascicles (anterior
or posterior) of the left bundle
branch are involved.
In this case the left anterior
fascicle is blocked and combined
with the RBBB this is called a
bifascicular block.
Posterior Fascicular Block
A 90 year old woman with syncope
Trifasicular Block
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Complete right bundle branch block
Left anterior hemiblock
Long PR interval
= bifasicular block with prolongation of the PR
interval
If the right bundle branch and both the anterior and
posterior fasicles of the left bundle branch were
blocked, this would be complete heart block.
Progression to Complete Heart Block
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Probably infrequent
Natural history of "high-risk" bundle-branch block: final
report of a prospective study. N Engl J Med. 1982 –
largest study, progression of 1% per year.
Smaller studies report 16-75%
80 Year Old Woman with dizzy spells
AF + Complete Heart Block
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Fibrillary waves of atrial fibrillation and no P
waves
Regular ventricular rhythm
19 Year Old Girl with Chest Pain
Pericarditis
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Stage I (acute phase): Diffuse concave upward ST
segment elevation in most leads, PR depression in most
leads (may be subtle), and sometimes notching at the end
of the QRS complex.
70 year old man with slow palpitations
Atrial Flutter
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5:1 Block
40 year old English Tourist with Central
Chest Pain and Shortness of Breath
Pulmonary Embolus
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Sinus tachycardia
Incomplete right bundle branch block
Possible old inferior myocardial infarction
S1Q3T3 pattern consistent with acute pulmonary
embolism (a large S wave in lead I, a Q wave in lead III,
and an inverted T wave in lead III indicates acute right
heart strain).
The most common ECG finding in the setting of a
pulmonary embolism is sinus tachycardia
54 year old farmer with hypertension
LVH Criteria
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Cornell criteria: Add the R wave in aVL and the S wave in V3. If the sum is > 28
mm in males or > 20 mm in females, then LVH is present.
Modified Cornell Criteria: Examine the R wave in aVL. If the R wave is > 12 mm
in amplitude, then LVH is present.
Sokolow-Lyon Criteria: Add the S wave in V1 plus the R wave in V5 or V6. If the
sum is > 35 mm, then LVH is present.
Romhilt-Estes LVH Point Score System:
If score = 4, then LVH present with 30-54% sensitivity. If score > 5, then LVH is
present with 83-97% specificity.
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Amplitude of largest R or S in limb leads >20 mm – 3
Amplitude of S in V1 or V2 > 30 mm – 3
Amplitude of R in V5 or V6 > 30 mm - 3
ST and T wave changes opposite QRS without digoxin – 3
ST and T wave changes opposite QRS with digoxin – 1
Left Atrial Enlargement – 3
Left Axis Deviation – 2
QRS duration > 90 milliseconds – 1
Intrinsicoid deflection in V5 or V6 > 50 millisecond - 1
26 year old international medical student
practicing ECG technique
Brugada
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pseudo-RBBB and persistent ST segment elevation in
leads V1 to V3
40 year old man on frusemide and sotolol
presents with collapse
Torsades de pointes
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Polymorphic VT associated with a prolonged QT interval
is termed torsades de pointes (TdP).
TdP can occur in patients who have a congenital long QT
syndrome or acquired QT prolongation from drug
therapy, hypomagnesemia, or hypokalemia.
91 year old man with palpitations
Sinus Tachycardia
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ST depression consistent with ischaemia