Case-oriented EKG’s(level 1- easiest

part two)MDFPR

July 8, 2009M. LaCombe

The normal EKG waveform

A normal EKG

The frontal plane (QRS) axis:

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 normalb)   The rhythm is sinus tachycardiac)   The PR interval is within normal limitsd)   There is a complete left bundle branch blocke)   The voltage in the chest leads meets criteria for left ventricular hypertrophy

a)   The QRS axis is normalb)   The rhythm is sinus tachycardiac)   The PR interval is within normal limitsd)   There is a complete left bundle branch blocke)   The voltage in the chest leads meets criteria for left ventricular hypertrophy

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 second2. A wide deep QS complex in V13. A wide tall R wave in V6

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.

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 prolongedb)   The QRS axis is normalc)   There is normal R wave progressiond)   There is a complete right bundle branch blocke)   There is evidence of right ventricular hypertrophy 

a)   The PR interval is prolongedb)   The QRS axis is normalc)   There is normal R wave progressiond)   There is a complete right bundle branch blocke)   There is evidence of right ventricular hypertrophy 

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).

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.

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 tachycardiab)   The QRS axis is normalc)   The precordial transition zone is in lead V3d)   There is probable left ventricular hypertrophye)   The PR interval is within normal limits

a)   The rhythm is sinus tachycardiab)   The QRS axis is normalc)   The precordial transition zone is in lead V3d)   There is probable left ventricular hypertrophye)   The PR interval is within normal limits

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.

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 rate3. 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 interval5. Check the P wave size6. Check the QRS width7. Check the QT interval8. Check the mean QRS electrical axis9. Check the QRS voltage10. Check the R wave progression in the chest leads11. Look for abnormal Q waves12. Look for ST segment abnormalities13. Look for T wave abnormalities14. Look for prominent U waves

Case #16:

This ECG from an 18 year old male shows all of the following EXCEPT?

a)   Normal variant early repolarization patternb)   Physiologic sinus arrhythmiac)   Normal AV conductiond)   Left axis deviatione)   Transition zone in lead V3

a)   Normal variant early repolarization patternb)   Physiologic sinus arrhythmiac)   Normal AV conductiond)   Left axis deviatione)   Transition zone in lead V3

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.

Case #17Which one of the following statements about this ECG from a 24- year-old male is CORRECT?

a)   The ECG shows right ventricular hypertrophyb)   The ECG shows left ventricular hypertrophyc)   The ECG is within the normal limitsd)   The ECG is consistent with severe hypokalemiae)   The ECG shows left atrial abnormality

a)   The ECG shows right ventricular hypertrophyb)   The ECG shows left ventricular hypertrophyc)   The ECG is within the normal limitsd)   The ECG is consistent with severe hypokalemiae)   The ECG shows left atrial abnormality

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.

Case #18ECG diagnosis is sinus rhythm with what conduction abnormality?

a)   Complete right bundle branch blockb)   Complete left bundle branch blockc)   Wolff-Parkinson-White pre-excitation (right sided bypass tract)d)   Left anterior fascicular blocke)   Left posterior fascicular block

a)   Complete right bundle branch blockb)   Complete left bundle branch blockc)   Wolff-Parkinson-White pre-excitation (right sided bypass tract)d)   Left anterior fascicular blocke)   Left posterior fascicular block

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.

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.)

Case #19

What is the cardiac rhythm?

a)   Sinus with a single premature ventricular complexb)   Sinus with SA exit blockc)   Sinus with A-V Wenckebachd)   Sinus with a single premature atrial complexe)   Respiratory sinus arrhythmia

a)   Sinus with a single premature ventricular complexb)   Sinus with SA exit blockc)   Sinus with A-V Wenckebachd)   Sinus with a single premature atrial complexe)   Respiratory sinus arrhythmia

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.

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.

Minor Segue:

Homework Assignments for Next Week:

1. Who is Diana Prince?

2. Who is Linda Danvers?

3. What is Hestia chiefly known for?

4. What is Ondine’s Curse?

5. Which 3rd year resident once called

this home?

6. Name one member of the band Circle of Willis.

7. Who goes by Red, plays the saxaphone, and likes Ursula Le Guin?

Case #20

What is the rhythm in this 68 year-old female?

a)   Multifocal atrial tachycardiab)   Wandering atrial pacemakerc)   Atrial fibrillation with rapid ventricular responsed)   Atrial flutter with rapid ventricular responsee)   Sinus arrhythmia with tremor artifact

a)   Multifocal atrial tachycardiab)   Wandering atrial pacemakerc)   Atrial fibrillation with rapid ventricular responsed)   Atrial flutter with rapid ventricular responsee)   Sinus arrhythmia with tremor artifact

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.

Case #21

What is the rhythm in this asymptomatic 47 year-old man? 

a)   Sinus with pre-excitation variantb)   Atrial tachycardia with 2:1 blockc)   Respiratory sinus arrhythmiad)   Ectopic atrial rhythme)   AV junctional escape rhythm

a)   Sinus with pre-excitation variantb)   Atrial tachycardia with 2:1 blockc)   Respiratory sinus arrhythmiad)   Ectopic atrial rhythme)   AV junctional escape rhythm

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.

Case #22

All of the following are present in this ECG from a 13 year old boy EXCEPT?

a)   Sinus bradycardiab)   Intraventricular conduction delayc)   ST elevations consistent with early repolarization variantd)   T wave inversions V1-V2 consistent with (juvenile physiologic variante)   Physiologic precordial transition zone

a)   Sinus bradycardiab)   Intraventricular conduction delayc)   ST elevations consistent with early repolarization variantd)   T wave inversions V1-V2 consistent with (juvenile physiologic variante)   Physiologic precordial transition zone

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.

Case #23This ECG from a 23 year-old female is most consistent with which diagnosis? 

a)   Left atrial abnormalityb)   Anterior ischemiac)   Normal variant T wave inversions V1-V2d)   Hypokalemiae)   Left ventricular hypertrophy

a)   Left atrial abnormalityb)   Anterior ischemiac)   Normal variant T wave inversions V1-V2d)   Hypokalemiae)   Left ventricular hypertrophy

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.

Case #24

24 year-old male seen for complaints of palpitations. What is the rhythm? 

a)   Sinus rhythm with sinus pausesb)   Sinus rhythm with atrial premature beatsc)   Respiratory sinus arrhythmiad)   Ectopic atrial rhythme)   Sinus rhythm with AV Wenckebach

a)   Sinus rhythm with sinus pausesb)   Sinus rhythm with atrial premature beatsc)   Respiratory sinus arrhythmiad)   Ectopic atrial rhythme)   Sinus rhythm with AV Wenckebach

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.

Case #25

This ECG most consistent with which single drug effect?

a)   Digoxinb)   Quinidinec)   Carvedilold)   Flecainidee)   Mexiletine

a)   Digoxinb)   Quinidinec)   Carvedilold)   Flecainidee)   Mexiletine

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.

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.