SECTION 3

Quiz Master: Self-Assessment

of Clinical ECG Skills

QUESTIONS Life-Savers: Stat ECG Diagnoses

This online section, designed for additional skill The following five patients all have different life-
mastery, includes 50 questions of varying levels of threatening problems that you can diagnose from
difficulty, ranging from entry level to much more their ECGs without any further history.
challenging. Good luck! This part is self-scored.
Working in small groups may be helpful.

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 1 60-year-old man

e72
 SECTION 3 Questions e73

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 2 50-year-old man

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 3 68-year-old man

III

Case 4 75-year-old woman

e74 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 5 52-year-old man

Triage Tryout transporting them to the nearest hospital, which is

Two patients arrive in your clinic office at the same 15 miles away. Who gets the taxi; who gets the
time. Both complain of severe chest discomfort. One ambulance?
ambulance and one taxicab are available for

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 6 50-year-old man with chest pain

 SECTION 3 Questions e75

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 7 50-year-old man with chest pain

Four Cases of Mistaken Identity

The following ECGs are commonly incorrectly
identified as shown. For each ECG, what is your
correct diagnosis?

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 8 “Left bundle branch block or left ventricular hypertrophy with inferior myocardial infarction”
e76 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

II

Case 9 “Complete heart block”

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 10 “Sinus (or ectopic atrial) tachycardia”

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 11 “Right axis deviation resulting from lateral wall infarction”

 SECTION 3 Questions e77

Syncopated Rhythms
Both these patients are complaining of palpitations,
characterized as an “irregular heartbeat sensation.”
What are the diagnoses?

II

Case 12

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 13
e78 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

Incomplete Diagnoses of Complete is only part of the story, however. What else is
Right Bundle Branch Block going on?
Right bundle branch block was correctly diag-
nosed in these two patients with chest pain. That

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 14

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 15
 SECTION 3 Questions e79

Morphing P Waves
What subtle arrhythmia is present in this ECG?

II

Case 16

Tearful Patient
Why is this healthy female crying? (Clue: Consider
the QRS duration.)

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 17
e80 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

Tricky Business from a previous one, at which time the workup

An ECG is obtained in this 45-year-old businessman revealed normal cardiac function. What is the
before he undergoes appendectomy. He complains diagnosis?
of lower left quadrant pain. The ECG is unchanged

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 18

Heart Failure After Myocardial on chest auscultation, distended neck veins while
Infarction sitting, and an S3 gallop. His ECG is unchanged
Two months after having a myocardial infarction, from a month ago and serum cardiac enzymes are
this 75-year-old man presents with bibasilar rales negative. What does the ECG show?

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 19
 SECTION 3 Questions e81

Common Theme arrhythmias? What is the probable common underly-

These elderly women both have chronic heart failure ing problem?
and both complain of nausea. What are the two

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 20 (Clue: Previous ECGs showed atrial fibrillation with a rapid rate.)

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 21 (Clue: Look very carefully at leads II and V1.)

e82 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

Drug Dilemma c. Amiodarone

This ECG (from a patient with normal serum d. Metoprolol
electrolytes) is most consistent with therapy using e. Verapamil
which one of the following drugs? f. None of the above
a. Digoxin
b. Lisinopril

V2 V5

V3 V6

Case 22

Narrowed-Down Differential Diagnoses and the other has pulmonary (pulmonic) valve
The following patients both have severely stenotic stenosis. Can you tell which ECG is from which
(narrowed) heart valves. One has mitral stenosis, patient?

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 23
 SECTION 3 Questions e83

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 24

Pause for Thought monitor lead show, which may be a clue to her
A 72-year-old woman has intermittent lightheaded- symptoms?
ness near-syncope. What does this single ECG

Monitor lead

Case 25
e84 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

Look-Alike Tachycardias other has paroxysmal supraventricular tachycardia

The following patients both complain of a fast (PSVT) due to atrioventricular nodal reentrant
heartbeat. One has atrial flutter with 2 : 1 block. The tachycardia (AVNRT). Which is which?

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 26

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 27
 SECTION 3 Questions e85

Silent History cardiovascular problems. However, what does his

A 75-year-old man has an ECG before undergoing ECG show?
cataract surgery. He denies a history of previous

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 28

Three Patients with Recurrent Syncope

The following three patients (Cases 29–31) report
recurrent episodes of fainting, confirmed by family
members. Can you diagnose the cause in each case?

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 29 21-year-old woman on no medications with normal serum electrolyte values

e86 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 30 37-year-old man

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 31 75-year-old woman

 SECTION 3 Questions e87

Heartburn
This 52-year-old man has a history of recent “indiges-
tion,” nausea, and an irregular pulse. What is the
rhythm? What is the major underlying problem?

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

II

Case 32

Hidden P Wave “ST-ories”

Can you diagnose these two arrhythmias?

II

Case 33

II

Case 34
e88 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

Myocardial Infarction Simulator had a myocardial infarction. What alternative life-

This 46-year-old man has chest discomfort and threatening diagnosis would account for all these
profound dyspnea. Initially he was thought to have findings?

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 35

Irregular Behavior
The following highly irregular rhythms are often
confused. What is the arrhythmia in each case?

II

Case 36

II

Case 37
 SECTION 3 Questions e89

Quick Changes activity and intermittently wide duration QRS

These two rhythm strips show underlying sinus complexes. What are the diagnoses?
rhythm with abrupt changes in cardiac electrical

II

Case 38

II

V1

Case 39
e90 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

Missing Bifocals
A middle-aged cardiologist left her bifocals at home
and nearly overlooked the following diagnosis. (Clue:
See arrow.)

II

V2

Case 40

Long and Short of It The key to their treatable diagnoses relates to the
Both these patients have mental status changes. Can beginning of the ST segment.)
you diagnose the cause from the ECG alone? (Clue:

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 41 30-year-old woman

 SECTION 3 Questions e91

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 42 65-year-old man

Pacemaker Plus with shortness of breath and evidence of pulmonary

This 78-year-old man has a VVI pacemaker for edema. In addition to the expected pacemaker
complete heart block. He comes into your office pattern, what does his ECG show?

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 43
e92 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

ECG/Coronary Arteriogram Matchup

Assign the ECG (A to D) that matches up best with
the history given immediately below (Cases 44to 47)
for these four middle-aged men.

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

B
 SECTION 3 Questions e93

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 44 This man had chest discomfort 3 days Case 45 This man has had chest pain for the past
ago. His serum creatine kinase and troponin levels 4 hours. His creatine kinase level is 800 U/L (normal:
are normal. He is found to have an occluded large less than 200 U/L) and he has a markedly elevated
left circumflex coronary artery and a severe infero- troponin level. He has severe three-vessel coronary
postero-lateral wall motion abnormality. disease with 80% to 90% proximal stenosis of the
e94 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

epicardial major coronary arteries, along with an ventricular wall motion and coronary arteries appear
anterior wall motion abnormality. normal, based on echocardiography and coronary
Case 46 This man had chest pain 1 month ago. His arteriography.
serum troponin level is now normal. Currently, he
is complaining of dyspnea. His coronary angiogram Calculation Leads to Diagnosis
reveals an occluded proximal left anterior descend- A 40-year-old woman complains about feeling weak.
ing coronary artery, with an anterior wall aneurysm She is not taking any medication. A previous ECG
noted on cardiac echocardiography. was within normal limits. Based on the present ECG,
Case 47 This man has had chest pain for 12 hours what laboratory values do you want to check as a
with a normal troponin level on evaluation. His left priority?

Lead II

Case 48

Interest-Piquing T Waves
What underlying, life-threatening condition explains
all findings? (Additive clues: QRS voltage, P waves,
and QTc interval.)

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Case 49
 SECTION 3 Answers e95

Fitting Finale

II

Case 50

ANSWERS V3, I, and aVL, with slow R wave progression in leads

Case 1 V1 to V3. In addition, note the ST depressions in
Severe hyperkalemia. Note the markedly prolonged leads II, III, and aVF, consistent with reciprocal changes.
PR interval, peaked T waves, and widened QRS This patient needs an ambulance stat.
complex.
Case 8
Case 2 Wolff–Parkinson–White (WPW) pattern. Note the
Anterior wall ST segment elevation myocardial classic trio of: short PR intervals, wide QRS com-
infarction (STEMI). Note the marked ST elevations plexes, and delta waves (i.e., slurring of the early
(and hyperacute T waves) in leads V1 through V6, I, part of the QRS complexes in leads I, aVL, V1, V2,
and aVL, with reciprocal ST depressions in leads III and other leads). The polarity of the delta waves
and aVF. Q waves are present in leads V3 through (slightly positive in V1 and V2 and positive in
V6. Also note left axis deviation with possible prior the lateral chest leads) and the overall QRS axis
inferior wall infarction. (horizontal) are most consistent with a right-sided
bypass tract.
Case 3
Sustained monomorphic ventricular tachycardia. Case 9
Note the wide complex tachycardia (QRS duration Sinus rhythm with isorhythmic AV dissociation (but
up to 0.20 sec) with a wide R wave in lead V1, a QS not complete heart block!). This patient does not
wave in lead V6, and extreme axis deviation. require a pacemaker.

Case 4 Case 10
Sinus rhythm with complete (third-degree) heart Atrial flutter with 2 : 1 AV block.
block. Note the idioventricular (or very slow junc-
tional) escape rhythm at about 33 beats/min. Case 11
Left–right arm lead (electrode) reversal, which
Case 5 accounts for the negative P waves and negative QRS
Sinus tachycardia with electrical alternans. This complexes in lead I.
combination is highly specific for pericardial effusion
with tamponade. Case 12
Sinus rhythm with Wenckebach type (Mobitz I)
Case 6 AV block.
Acute pericarditis. Note the diffuse ST segment eleva-
tions (leads I, II, III, aVF, and V3 to V6) with PR Case 13
segment deviations (up in lead aVR, down in leads Atrial tachycardia at 150 beats/min with variable
V4 to V6). This patient gets the taxi. AV block.

Case 7 Case 14
Acute ST segment elevation anterior myocardial Right bundle branch block with acute anterior ST
infarction. ST elevations are localized to leads V1 to segment elevation/Q wave myocardial infarction.
e96 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

Note the prominent Q waves in leads V1 to V3, with of this arrhythmia is digitalis toxicity. The ECG
ST elevations in leads V1 to V5 and lead aVL. shows low voltage in the extremity (limb) leads.
Based on the very slow (“poor”) precordial lead
Case 15 R wave progression, this patient may have had a
Right bundle branch block with anterior sub- previous anterior myocardial infarction. Based on
endocardial ischemia. Note the ST segment the prominent precordial voltage, left ventricular
depressions in leads V2, V3, and V4; also left axis hypertrophy (LVH) is likely present. The abnormal
deviation. ST-T changes are nonspecific, and consistent with
digitalis toxicity, ischemia, and LVH, singly or in
Case 16 combination.
Wandering atrial pacemaker (WAP). Do not confuse The theme common to Cases 20 and 21, therefore,
this slow rhythm (a relative of sinus bradycardia) is digitalis (digoxin) toxicity.
with multifocal atrial tachycardia (MAT). WAP, per
se, may be seen normally with increased vagal tone Case 22
or, nonspecifically, in the context of sinus brady- c. Amiodarone effect. Note the prominently pro-
cardia due to multiple causes. longed QT(U) interval.

Case 17 Case 23
Healthy (and hungry) neonate. Note the very narrow Pulmonary (pulmonic) valve stenosis. The ECG
QRS complex (about 0.06 sec) with a rightward axis, shows signs of right ventricular hypertrophy (rela-
tall R wave in lead V1, and high sinus rate (125 beats/ tively tall R waves in lead V1 with right axis deviation)
min). All of these findings are appropriate for the and right atrial abnormality.
patient’s age.
Case 24
Case 18 Mitral valve stenosis. The ECG shows signs of right
Dextrocardia with situs inversus. Note the apparently ventricular hypertrophy (i.e., relatively tall R waves
reversed limb and chest leads. This patient has a in lead V1 with right axis deviation) along with
normal heart (right side of chest) with an inflamed prominent left atrial abnormality.
appendix (left side of lower abdomen!).
Case 25
Case 19 2 : 1 sinoatrial (SA) block causes an entire P–QRS–T
Sinus rhythm with a prolonged PR interval (“first- cycle to be “dropped.” This patient had symptomatic
degree” AV block). The ECG also shows left atrial sick sinus syndrome and required a permanent
abnormality, left ventricular hypertrophy, and right pacemaker.
bundle branch block. Q waves and ST segment
elevations are seen in leads V1 through V5, I, and Case 26
aVL. The findings are consistent with a left ven- AV nodal reentrant (reentry) tachycardia (AVNRT),
tricular aneurysm, which was confirmed with a type of PSVT. In some of the beats small
echocardiography. retrograde P waves (negative in lead II, positive
in lead aVR) are visible immediately after the
Case 20 QRS complex, at the very beginning of the ST
Atrial fibrillation with a slow and at times regularized segment (so-called pseudo-S and pseudo-R waves,
ventricular response should make you suspect respectively).
digitalis toxicity. The ST-T changes are nonspecific
but consistent with digitalis effect (and/or with Case 27
ischemia or with hypertrophy). Atrial flutter with 2 : 1 AV conduction. Note the
flutter waves at a rate of 300 beats/min (e.g., leads
Case 21 aVR, aVL and V1.The presentation is consistent with
Atrial tachycardia with 2 : 1 AV block. (A very subtle typical atrial flutter, with a counterclockwise motion
“extra” P wave in the ST segment is best seen in of the macro-reentrant flutter wave around the right
leads V1 and V2.) An important, but rare cause atrium (isthmus-dependent).
 SECTION 3 Answers e97

Case 28 is 160 beats/min with a ventricular rate of 80

Infero-postero-lateral myocardial infarction. Note beats/min.
the Q waves in leads II, III, aVF, V5, and V6, and the
tall R waves in leads V1 and V2. Case 35
Acute right ventricular overload (cor pulmonale),
Case 29 in this case due to massive pulmonary embolism.
Sinus rhythm with a markedly prolonged QT(U) Note the sinus tachycardia, SIQIIITIII pattern, slow
interval (about 0.6 sec). This patient has a hereditary R wave progression, and prominent anterior T wave
(congenital) type of long QT syndrome, associated inversions. The latter are consistent here by right
with a “channelopathy.” Syncope was caused by ventricular overload (sometimes called a right
recurrent episodes of torsades de pointes type of ventricular “strain” pattern).
ventricular tachycardia. Work-up and therapy in
this context usually involve genetic testing, ICD Case 36
implantation and beta blockade, as well as family Multifocal atrial tachycardia (MAT).
member evaluation, under the care of a cardiac
electrophysiology team. Case 37
Atrial fibrillation (AF).
Case 30
Atrial fibrillation with the Wolff–Parkinson–White Case 38
(WPW) syndrome. The clues to this diagnosis are Sinus rhythm with intermittent left bundle branch
the extremely rapid wide-complex tachycardia (about block (LBBB). The first three sinus beats are con-
300 beats/min at times) with a very irregular rate. ducted with a left bundle branch block pattern; the
This rhythm constitutes a medical emergency since next three sinus beats occur with a normal QRS
it may spontaneously degenerate into ventricular complex. Careful inspection reveals that the disap-
fibrillation. pearance of the LBBB is associated with rate slowing
of the sinus rate. Therefore, the LBBB here is likely
Case 31 related to an increase in the rate, a finding referred
Sinus rhythm at 100 beats/min with advanced second- to as acceleration- or tachycardia-dependent bundle
degree AV block (3 : 1 conduction pattern). The QRS branch block.
complexes show a bifascicular block pattern (right
bundle branch block and left anterior fascicular Case 39
block). Evidence for left atrial abnormality/left Sinus rhythm with transient accelerated idioventricular
ventricular hypertrophy is also present. Note that rhythm (AIVR). This rhythm may occur without
one of the P waves is partly hidden in the T waves (see apparent cause as an escape mechanism with slowing
V1). The patient required a permanent pacemaker. of the sinus rate or in “competition” with the sinus
rate. In this case, the AIVR episode is initiated by a
Case 32 premature ventricular complex (PVC). Note the
Sinus rhythm at 95 beats/min with a 4 : 3 Wencke- underlying AV dissociation. A classic setting of AIVR
bach AV block. Note the group beating pattern is after coronary artery occlusion and reperfusion,
associated with this type I AV block. Of major note, occurring either spontaneously, or after a percutane-
this arrhythmia was due to an acute/evolving ST ous coronary (angioplasty) intervention or with
elevation/Q wave inferior myocardial infarction. thrombolysis therapy.

Case 33 Case 40
Junctional rhythm at 60 beats/min. Note the negative Sinus rhythm with atrial bigeminy marked by blocked
(retrograde) P waves partly “hidden” at the end of (nonconducted) atrial premature atrial complexes
the ST segments. (blocked PACs). The arrow points to a subtle P wave
from an atrial premature atrial complex (beat). Note
Case 34 that each premature P wave comes so early in
Atrial tachycardia with 2 : 1 AV block. Note the the cardiac cycle that it fails to conduct through
“hidden” P wave in the ST segments. The atrial rate the AV node, which is still refractory following the
e98 SECTION 3 Quiz Master: Self-Assessment of Clinical ECG Skills

previous sinus beat. Note also that the effective inferolateral leads), virtually diagnostic of acute
ventricular rate here is about 50/min, mimicking a pericarditis.
sinus bradycardia. This arrhythmia must also be
distinguished from sinus rhythm with 2 : 1 AV block, Case 48
in which sinus P waves come “on time” but fail to This patient had hypocalcemia. Calculate the QTc,
conduct through the AV junction because of second- with QT = 0.48 sec and RR = 0.85 sec.
degree AV heart block. Using the square root formula:

Case 41 QTc = 0.58 0.85 = 0.52 sec or 520 msec

Hypercalcemia. Note the relatively short QT interval
Using an alternative linear formula (see Chapter 3)
due to an abbreviated ST segment such that the T
one gets:
wave appears to take off right from the end of the
QRS complex. QTc = 480 msec + 1.75 (10.6) = 499 msec
Case 42 Therefore the QTc is clearly prolonged here by both
Systemic hypothermia. Note the characteristic J correction methods. Further inspection shows that
(Osborn) waves, best seen in leads V3 to V5. These the prolonged QTc appears due to a long (“stretched-
“humped” waves appear as convex “out-pouchings” out”) ST segment, rather than a broad T wave. Thus
at J point, the locus that defines the junction between the most likely diagnosis is hypocalcemia. In contrast,
the end of the QRS and beginning of the ST segment. hypokalemia generally flattens the T wave and
prolongs the QT(U) interval. The ECG indicates the
Case 43 importance of checking serum calcium and phos-
Acute inferolateral ST elevation myocardial infarc- phate, magnesium and potassium levels, in addition
tion (STEMI) superimposed on a ventricular to other relevant laboratory tests.
pacemaker pattern. Note the ST elevations in leads
II, III, aVF, V5, and V6, and the reciprocal ST depres- Case 49
sions in leads V1 to V3. Note the combination of the tall peaked T waves
from hyperkalemia with the voltage criteria for left
Case 44 ventricular hypertrophy (LVH). Left atrial abnormal-
B. Diffuse, marked ST depressions (except, impor- ity is also present. Patients with chronic renal failure
tantly, in lead aVR), most apparent in the anterior typically have hypertension, leading to LVH. QT
leads. These findings are consistent with non-ST prolongation may also be present in this context
segment myocardial infarction. This constellation from concomitant hypocalcemia (associated with
of findings usually indicates severe three vessel increased phosphate levels and abnormal vitamin
coronary disease, and sometimes left main coronary D metabolism). Therefore, the ECG triad of peaked
disease. T waves (consistent with hyperkalemia), QT (ST
phase) prolongation (consistent with hypocalcemia),
Case 45 and LVH (consistent with hypertension) should
A. Q waves and ST-T changes consistent with evolv- strongly suggest chronic renal failure.
ing ST segment elevation infero-postero-lateral
myocardial infarction. Case 50
Cardiac arrest! The rhythm strip shows sinus
Case 46 rhythm with ST segment depressions that are
C. Q waves and persistent ST elevations consistent consistent with ischemia, followed by the abrupt
with anterior wall infarction and ventricular onset of ventricular flutter (very rapid, “sinusoidal”
aneurysm. ventricular tachycardia such that the QRS and T
cannot be distinguished) degenerating quickly into
Case 47 ventricular fibrillation. Emergency institution of the
D. Diffuse concave ST elevations and characteristic CPR protocol is required, with defibrillation as soon
PR segment deviations (up in aVR and down in the as possible.