5. Case #13
A 61-year-old man with a history of hypertension and
congestive heart failure presents to the emergency
department with shortness of breath after eating
breakfast. All of the following statements about his ECG
are correct EXCEPT:
a) The QRS axis is normal
b) The rhythm is sinus tachycardia
c) The PR interval is within normal limits
d) There is a complete left bundle branch block
e) The voltage in the chest leads meets criteria for
left ventricular hypertrophy
6. The QRS axis is normal
The rhythm is sinus tachycardia
The PR interval is within normal limits
There is a complete left bundle branch block
The voltage in the chest leads meets criteria for left ventricular hypertrop
7. d) There is no left bundle branch block (LBBB).
The QRS axis is normal at approximately 0. The rate is
approximately 100 beats per minute, and there are
upright P waves in lead II, fulfilling the criteria for sinus
tachycardia. This patient is likely tachycardic because of
neurohormonal changes related to congestive heart
failure (CHF) exacerbation, namely increased
sympathetic tone and decreased vagal tone. The PR
interval is normal at 0.16 second (normal PR < 0.20
second). There is ECG evidence of left ventricular
hypertrophy (see below).
The criteria for complete LBBB include:
1. QRS duration > 0.12 second
2. A wide deep QS complex in V1
3. A wide tall R wave in V6
8. Additional comments:
LVH can lead to a number of ECG abnormalities, including
prominent voltage in the chest leads and selected limb leads, a
widened QRS, T wave inversions in leads with tall R waves, left
axis deviation, and left atrial abnormality (LAA). Voltage criteria for
left ventricular hypertrophy (LVH) should be used with caution, as
various criteria have limited sensitivity or specificity. Commonly
used voltage criteria include one or more of the following:
1. SV1 + RV5 or V6 > 35 mm (3.5 mV)
2. RaVL > 11 mm (1.1 mV)
3. For men: SV3 + RaVL > 28 mm (2.8 mV)
4. For women: SV3 + RaVL > 20 mm (2.0 mV)
This ECG shows clear evidence of LVH with LAA, T wave
inversions in the lateral leads, and very prominent voltage in the
chest leads (SV1 + RV5 = 45 mm).The lateral T wave inversions
could be related to LVH or they could indicate lateral wall ischemia.
However, this patient’s serial cardiac enzymes were all negative.
His shortness of breath was due to worsening of his CHF, resulting
in pulmonary edema. He improved with standard therapy.
9. Case #14
A 76-year-old woman who has had severe
asthma since age 18 comes to the emergency
department complaining of increased shortness
of breath. Which one of the following
statements is true concerning her admission
ECG?
a) The PR interval is prolonged
b) The QRS axis is normal
c) There is normal R wave progression
d) There is a complete right bundle branch
block
e) There is evidence of right ventricular
hypertrophy
10. a) The PR interval is prolonged
b) The QRS axis is normal
c) There is normal R wave progression
d) There is a complete right bundle branch block
e) There is evidence of right ventricular hypertrophy
11. E) There is evidence of right ventricular hypertrophy
Sinus rhythm is present with a relatively fast resting rate
(93/min). The PR interval is normal at approximately 0.16
second (normal PR < 0.20 second). The QRS axis is
approximately 180(biphasic in lead aVF and positive in lead
aVR) and thus dramatically deviated to the right. The R wave
progression is reversed, with tall right precordial R waves and
an rS complex in the left chest leads!Recall that in the normal
ECG, there is an rS complex in lead V1. The R wave becomes
relatively larger and the S wave smaller in lead V2. The ratio
of the R wave to the S wave becomes 1 at the so-called
transition zone, usually in lead V3 or V4. By lead V6, the QRS
complex has usually evolved to become a qR complex. This
process is referred to as normal R wave progression. In this
ECG, however, there is a qR complex in lead V1 and an rS
complex in lead V6.There is an incomplete, not complete right
bundle branch block (RBBB) (QRS duration between 0.10 and
0.12 second).The tall right precordial R waves (with a qR
complex in lead V1) and the right axis deviation (RAD) are
essentially diagnostic of right ventricular hypertrophy
(RVH.)The ST-T changes in V1-V3 are also consistent with RV
overload (sometimes called an RV strain pattern). The P
waves in lead II are slightly peaked but do not meet strict
criteria for right atrial overload (2.5mm or more in height).
12. Additional comments:
RV hypertrophy occurs over time in response to
pressure or volume overload in conditions such as
primary pulmonary hypertension, chronic obstructive
pulmonary disease (COPD), pulmonic stenosis, and
atrial septal defect (ASD). This patient was diagnosed
with an asthma exacerbation superimposed on severe
COPD and improved with oral steroids and albuterol
nebulizer therapy.
13. Case #15:
A 55-year-old man was admitted to the hospital
for a bleeding peptic ulcer. His admission ECG
is notable for the all of the following EXCEPT:
a) The rhythm is sinus tachycardia
b) The QRS axis is normal
c) The precordial transition zone is in lead
V3
d) There is probable left ventricular
hypertrophy
e) The PR interval is within normal limits
14. a) The rhythm is sinus tachycardia
b) The QRS axis is normal
c) The precordial transition zone is in lead V3
d) There is probable left ventricular hypertrophy
e) The PR interval is within normal limits
15. d) There is probable left ventricular hypertrophy
The rate is approximately 100 beats per minute, and
there are upright P waves in lead II, fulfilling the criteria
for sinus tachycardia. This patient is likely tachycardic
because of volume depletion and anemia secondary to
blood loss. The QRS axis is normal at +15. The
transition zone is in lead V3, where the ratio of R wave
to S wave equals approximately 1. The PR interval is
normal at 0.17 second (normal PR < 0.20 second).
There is no ECG evidence of left ventricular hypertrophy
(LVH), such as prominent voltage in the chest leads, left
ventricular conduction delay, T wave inversions in leads
with tall R waves, left axis deviation, or left atrial
abnormality.
16. Let’s take a moment to review the steps you should follow
every time you read an ECG.
Try to get into the habit of following the steps in the same
order each time:
1. Check the standardization and quality of the ECG (The
usual calibration is 25 mm/sec and 10mm/mV)
2. Calculate the heart rate
3. Analyze the rhythm (Is it sinus; sinus plus ectopic beats; or
some entirely non-sinus mechanism such as atrial fibrillation,
ventricular tachycardia or a junctional escape rhythm?)
4. Check the PR interval
5. Check the P wave size
6. Check the QRS width
7. Check the QT interval
8. Check the mean QRS electrical axis
9. Check the QRS voltage
10. Check the R wave progression in the chest leads
11. Look for abnormal Q waves
12. Look for ST segment abnormalities
13. Look for T wave abnormalities
14. Look for prominent U waves
17. Case #16:
This ECG from an 18 year old male shows all of the
following EXCEPT?
a) Normal variant early repolarization pattern
b) Physiologic sinus arrhythmia
c) Normal AV conduction
d) Left axis deviation
e) Transition zone in lead V3
18. a) Normal variant early repolarization pattern
b) Physiologic sinus arrhythmia
c) Normal AV conduction
d) Left axis deviation
e) Transition zone in lead V3
19. d) Left axis deviation
This ECG shows a normal variant that is commonly referred to as
early repolarization pattern." There are ST elevations in leads V2-
V6 and in some of the limb leads. Slight notching of the terminal
QRS (V4) is often seen in conjunction with this pattern. The ST
segment retains its normal upward concavity. The QRS axis here is
normal (about +30 degrees). The QRS transition zone (R=S) is in
lead V3, a normal finding. AV conduction is normal, indicated by
the normal PR interval (about 0.14 sec.) The slight variation in
heart rate is due to physiologic (respiratory) sinus arrhythmia.
20. Case #17
Which one of the following statements about this ECG
from a 24- year-old male is CORRECT?
a) The ECG shows right ventricular
hypertrophy
b) The ECG shows left ventricular
hypertrophy
c) The ECG is within the normal limits
d) The ECG is consistent with severe
hypokalemia
e) The ECG shows left atrial abnormality
21. a) The ECG shows right ventricular hypertrophy
b) The ECG shows left ventricular hypertrophy
c) The ECG is within the normal limits
d) The ECG is consistent with severe hypokalemia
e) The ECG shows left atrial abnormality
22. c) The ECG is within the normal limits
The ECG shows sinus rhythm with a physiologic sinus
arrhythmia at an average rate of about 60 bpm and is
completely within the normal limits. The basic intervals
(PR interval 0.15 sec, QRS 0.09 sec, and QT 0.39 sec)
are all within normal limits. The P wave duration and
morphology are normal. The precordial leads show
normal R wave progression with very slight ST segment
elevations (V2-V6) consistent with normal variant early
repolarization. The QRS axis is normal at about +60
degrees. There is no evidence of left or right ventricular
hypertrophy.Severe hypokalemia generally causes
repolarization (QT-U) prolongation (usually with flat T
waves and sometimes ST sagging), often with
prominent U waves.
23. Case #18
ECG diagnosis is sinus rhythm with what
conduction abnormality?
a) Complete right bundle branch block
b) Complete left bundle branch block
c) Wolff-Parkinson-White pre-excitation
(right sided bypass tract)
d) Left anterior fascicular block
e) Left posterior fascicular block
24. a) Complete right bundle branch block
b) Complete left bundle branch block
c) Wolff-Parkinson-White pre-excitation (right sided bypass tract)
d) Left anterior fascicular block
e) Left posterior fascicular block
25. b) Complete left bundle branch block
The ECG shows sinus rhythm with a complete left
bundle branch block (LBBB) pattern (QRS duration 0.16
second) with secondary ST-T wave changes. Bundle
branch blocks usually have secondary T wave changes
such that the ST-T wave vector points opposite in
direction of the major vector of the QRS. These
secondary ST-T changes are due to the altered
sequence of ventricular activation. In a classic right
bundle branch block (RBBB), an rSR type complex will
be seen in V1. Wolff-White-Parkinson (WPW) pre-
excitation produces the classic triad a short PR, wide
QRS and delta waves, not present here. Left anterior
and left posterior fascicular blocks (hemiblocks) do not
cause prominent widening or the QRS duration, and are
associated with marked left (-45 degrees or more) or
right (+100 degrees or more) axis deviation,
respectively. Complete LBBB may be associated with a
normal, leftward, or rarely rightward axis.
26. LBBB may mask or mimic the pattern of
underlying myocardial infarction. LBBB
is also important since it is often a
marker of underlying organic heart
disease (e.g., due to hypertension,
severe coronary disease,
cardiomyopathy or valvular disease.)
27. Case #19
What is the cardiac rhythm?
a) Sinus with a single premature ventricular
complex
b) Sinus with SA exit block
c) Sinus with A-V Wenckebach
d) Sinus with a single premature atrial
complex
e) Respiratory sinus arrhythmia
28. a) Sinus with a single premature ventricular complex
b) Sinus with SA exit block
c) Sinus with A-V Wenckebach
d) Sinus with a single premature atrial complex
e) Respiratory sinus arrhythmia
29. d) Sinus with a single premature atrial complex
This ECG shows sinus rhythm, rate about 70
bpm with normal intervals and normal R wave
progression. A single isolated premature atrial
complex (PAC) (7th beat) is present. The P
wave comes very early and there is a slightly
different P wave morphology from the sinus
beats. The QRS complex is identical to sinus
beats. There is also evidence of physiologic
early repolarization variant with slight notching
of the J point in the antero-lateral leads, e.g.
lead V5. Respiratory sinus arrhythmia causes
more gradual increases and decreases in heart
rate associated with inspiration and expiration,
respectively.
30. Note that the terms premature beat, complex
and depolarization are used interchangeably.
These terms are preferable to premature
contractions since not all atrial or ventricular
premature depolarizations are actually
associated with a mechanical
response.Isolated atrial ectopy of this type is
very common and may be seen in physiologic
and pathologic contexts without any specific
clinical implications.
32. 1. Who is Diana Prince?
2. Who is Linda Danvers?
3. What is Hestia chiefly known
for?
4. What is Ondine’s Curse?
33. 5. Which 3rd year resident once
called this home?
34. 6. Name one member of the band Circle of Willis.
35. 7. Who goes by Red, plays the saxaphone, and likes
Ursula Le Guin?
36. Case #20
What is the rhythm in this 68 year-old female?
a) Multifocal atrial tachycardia
b) Wandering atrial pacemaker
c) Atrial fibrillation with rapid ventricular
response
d) Atrial flutter with rapid ventricular
response
e) Sinus arrhythmia with tremor artifact
37. a) Multifocal atrial tachycardia
b) Wandering atrial pacemaker
c) Atrial fibrillation with rapid ventricular response
d) Atrial flutter with rapid ventricular response
e) Sinus arrhythmia with tremor artifact
38. c) Atrial fibrillation with rapid ventricular response
This ECG shows atrial fibrillation with a rapid
ventricular response rate at about 120 bpm
with borderline right axis deviation. Non-
specific ST-T changes are present. There is
possible left ventricular hypertrophy and
possible biventricular hypertrophy.Multifocal
atrial tachycardia and wandering atrial
pacemaker are excluded as there is no
evidence of discrete P waves, either normal or
ectopic. Atrial flutter is excluded because of
the erratic response whereas in flutter there is
a more regularized response.
39. Case #21
What is the rhythm in this asymptomatic 47
year-old man?
a) Sinus with pre-excitation variant
b) Atrial tachycardia with 2:1 block
c) Respiratory sinus arrhythmia
d) Ectopic atrial rhythm
e) AV junctional escape rhythm
40. a) Sinus with pre-excitation variant
b) Atrial tachycardia with 2:1 block
c) Respiratory sinus arrhythmia
d) Ectopic atrial rhythm
e) AV junctional escape rhythm
41. d) Ectopic atrial rhythm
This ECG shows an ectopic atrial rhythm with inverted
(negative) P waves in lead 11,111, aVF, V5-V6. There is
a normal PR interval of 0.15 second. The apparently
short PR in V1 and V2 is due to the fact that the
beginning of the P wave is nearly isoelectric in these
leads (see simultaneously recorded lead II in rhythm
strip.) The QRS duration is normal (0.09 second.)Sinus
arrhythmia and sinus with pre-excitation are excluded as
there are no sinus P waves (upright in lead II
invariably). Junctional escape rhythms are usually at
slower rates and the P wave is typically hidden within
the QRS or appears just before or just after the QRS.
The P wave here occurs distinctly before the QRS
consistent with an ectopic atrial focus, probably left
atrial given the P wave axis.Ectopic atrial rhythms
(usually transient) may occur without organic heart
disease or with a variety of different cardiac syndromes.
The ECG here is otherwise entirely unremarkable.
42. Case #22
All of the following are present in this ECG
from a 13 year old boy EXCEPT?
a) Sinus bradycardia
b) Intraventricular conduction delay
c) ST elevations consistent with early
repolarization variant
d) T wave inversions V1-V2 consistent with
(juvenile physiologic variant
e) Physiologic precordial transition zone
43. Sinus bradycardia
Intraventricular conduction delay
ST elevations consistent with early repolarization variant
T wave inversions V1-V2 consistent with (juvenile physiologic vari
Physiologic precordial transition zone
44. b) Intraventricular conduction delay
This ECG shows sinus bradycardia at a rate of
55 bpm. The waveform morphologies are
physiologic for a 13 year old male, with slight
ST elevations V1 and V2 due to early
repolarization variant (and minimal T wave
inversions, consistent with the juvenile T wave
pattern). QRS duration is normal at about .07
second and AV conduction is normal at .16
second. The precordial transition zone in lead
V3 is physiologic.
45. Case #23
This ECG from a 23 year-old female is most
consistent with which diagnosis?
a) Left atrial abnormality
b) Anterior ischemia
c) Normal variant T wave inversions V1-V2
d) Hypokalemia
e) Left ventricular hypertrophy
46. a) Left atrial abnormality
b) Anterior ischemia
c) Normal variant T wave inversions V1-V2
d) Hypokalemia
e) Left ventricular hypertrophy
47. c) Normal variant T wave inversions V1-V2
This ECG shows sinus rhythm at a rate of
about 77 bpm. The basic intervals are normal:
PR 0.15 second, QRS 0.08 second and QT
0.35 second.
T wave inversions limited to leads V1-V2 are a
common physiologic variant in this age group,
sometimes referred to as a persistent juvenile
T wave pattern. More extensive anterior T
wave inversions in young adults may be seen
in a variety of settings, including
arrhythmogenic right ventricular dysplasia
(ARVD); see Circulation 2004; 110: 527.Left
atrial abnormality is ruled out as the P wave is
normal in amplitude and morphology. There is
no evidence of prominent U waves or QT/U
prolongation with flat T waves to indicate
hypokalemia. There is no evidence of left
ventricular hypertrophy.
48. Case #24
24 year-old male seen for complaints of
palpitations. What is the rhythm?
a) Sinus rhythm with sinus pauses
b) Sinus rhythm with atrial premature beats
c) Respiratory sinus arrhythmia
d) Ectopic atrial rhythm
e) Sinus rhythm with AV Wenckebach
49. a) Sinus rhythm with sinus pauses
b) Sinus rhythm with atrial premature beats
c) Respiratory sinus arrhythmia
d) Ectopic atrial rhythm
e) Sinus rhythm with AV Wenckebach
50. c) Respiratory sinus arrhythmia
This ECG shows a physiologic respiratory
sinus arrhythmia (RSA). The progressive
fluctuations in sinus rates are apparent in the
rhythm strip (lead II), going from fast at the
beginning to slow and then return back to fast
(rates vary from 84 to 60 and back to 84.) The
variability is dependent on cyclic changes in
vagal tone associated with the phases of
respiration. Ectopic atrial rhythm is excluded
as the P waves are consistent in morphology.
There are no prolonged sinus pauses and no
evidence of premature atrial beats and AV
conduction is normal.
51. Case #25
This ECG most consistent with which single
drug effect?
a) Digoxin
b) Quinidine
c) Carvedilol
d) Flecainide
e) Mexiletine
52. a) Digoxin
b) Quinidine
c) Carvedilol
d) Flecainide
e) Mexiletine
53. b) Quinidine
This ECG shows sinus rhythm at about 67 bpm with an
intraventricular conduction delay (QRS 0.12 second) and
a mildly prolonged QT-(U) interval of (0.46 second)
consistent with quinidine effect. A single isolated atrial
premature beat and left atrial abnormality are present.
The R wave is at the upper limits of normal in amplitude
in lead aVL with borderline voltage for left ventricular
hypertrophy. Hypokalemia was ruled out. This patient, a
63 year old man, with a history of systemic
hypertension, obstructive sleep apnea and paroxysmal
atrial fibrillation, had been treated with quinidine
gluconate for many years without adverse effect.
Echocardiogram showed normal systolic left ventricular
function. The patient was also taking diltiazem.
Quinidine toxicity associated with prominent QT (U)
prolongation can result in torsade de pointes ventricular
tachycardia.
54. Digoxin produces ‘scooped’ ST/T segments.
Carvedilol is a beta blocker and would produce a sinus
bradycardia.
Flecainide, a class 1c antiarrhythmic produces PR and
QRS prolongation.
Mexiletine is a class 1b agent in the same class as
lidocaine. It doesn’t produce any diagnostic EKG
changes.
