Approach to a patient with QRS complex abnormality in ECG

Case-1:
A 23 years old medical student presented with occasional palpitation, shortness of breath and chest discomfort. He had the following ECG.
A 53 years old gentleman presented with palpitations for last 5 hours. He is smoker, diabetic, dyslipidemic and hypertensive. He had exertional chest discomfort for last 5 years and did coronary angiogram 3 years back and CAG revealed TVD and advised for revascularization. But he refused and was irregular in medication and reluctant for life style modification. He came to emergency department with this ECG.

1. Fundamentals of ECG
Approach to a patient with QRS complex abnormalities
Dr. Md.ToufiqurRahman
MBBS, FCPS, MD, FACC, FESC, FRCP, FSCAI,
FCCP,FAPSC, FAPSIC, FAHA,FACP
Professor & head of Cardiology
CMMC, Manikganj
Ex professor of cardiology,
NICVD, Dhaka

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Fundamentals of ECG QRS Complex

3. Fundamentals of ECG
Conduction system of the heart

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Case-1:
A 23 years old medical student presented with occasional palpitation,
shortness of breath and chest discomfort. He had the following ECG.
Figure: Sinus rhythm: Each narrow QRS complex is preceded by a normal P wave.

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
A 53 years old gentleman presented with palpitations for last 5 hours. He is smoker,
diabetic, dyslipidemicand hypertensive. He had exertionalchest discomfort for last 5
years and did coronary angiogram 3 years back and CAG revealed TVD and advised
for revascularization. But he refused and was irregular in medication and reluctant
for life style modification. He came to emergency department with this ECG.
Figure: Junctionaltachycardia: Narrow QRS complexes with no visible
P waves.

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
A 44 years old gentleman presented with chest pain and excessive sweating
for 45 minutes. He is diabetic, normotensive, smoker. His BP was 80/70 mm
Hg. On he emergency department he has the following ECG.
Figure: Ventricular tachycardia: Broad QRS complexes with no visible P
waves. (Monomorphic VT)

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Right bundle branch blockproduces an RSR’ pattern in V1 and deep
slurred S waves in the lateral leads.
Left bundle branch blockproduces a dominant S wave in V1 with
broad, notched R waves and absent Q waves in the lateral leads.
Hyperkalaemiais associated with a range of abnormalities including
peaked T waves
Tricyclic poisoningis associated with sinus tachycardia and tall R’
wave in aVR
Wolff-Parkinson White syndromeis characterisedby a short PR
interval and delta waves
Ventricular pacingwill usually have visible pacing spikes
Hypothermiais associated with bradycardia, long QT, Osborn waves
and shivering artefact
How broad QRS can be identified by pattern recognition?

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Case-4: A 42 years old lady presented with palpitations and chest discomfort
and came to Emergency department with the following ECG.
Figure: Atrial flutter: Narrow QRS complexes are associated with
regular flutter waves.

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Case-5: A 15 years old boy presented with palpitations and shortness
of breath on exertion for last 2 years. He had the following ECG and on
color Doppler echocardiogram revealed mitral valve prolapse with
mitral regurgitation grade1+. He had no history of rheumatic fever.
Figure: ECG showing both narrow and broad complexes (ventricular
bigeminy)

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Ventricular Quadrigeminy

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Figure: ECG showing Couplets

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Figure: ECG of Non sustained VT
Definitions vary regarding 3 or more PVCs.
Some authors define three PVCs as a triplet of PVCs; whilst others
describe this as a ‘short burst of VT’; but more commonly as NSVT
A consensus definition would be: 3-30 consecutive PVCs with a rate
>100bpm described as non-sustained VT (ventricular rhythm if rate
<100bpm)

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Figure: ECG of a Supraventricular Bigeminylead 2

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Case-6: A 21 years old gentleman presented with palpitations and shortness of
breath on exertion for last 5 months. His pulse 104/min, low volume and
auscultation examination revealed ejection systolic murmur over the whole
precordium. His echocardiogram report revealed Severe aortic stenosis due to
Bicuspid aortic valve with concentric Left ventricular Hypertrophy. He had the
following ECG.
Figure: ECG showing Left ventricular hypertrophy with repolarization abnormality

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Case-7: A 25 years old obese lady presented with chest
discomfort for last 3 months. She had the following ECG.
Figure: ECG showing low voltage

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
The most important cause ismassive pericardial effusion, which produces a triad of:
oLow voltage
oTachycardia
oElectrical alternans
Patients with this triad need to be immediately assessed for clinical or
echocardiographic evidence of tamponade.
Other causes of low voltage include:
Fluid:Pericardial effusion;Pleural effusion
Fat:Obesity
Air:Emphysema;Pneumothorax
Infiltrative / Connective Tissue Disorders
Myxoedema
Infiltrative myocardial diseases —i.e.restrictive cardiomyopathydue to
amyloidosis, sarcoidosis, haemochromatosis
Constrictive pericarditis
Scleroderma
Loss of viable myocardium:Previous massive MI; End-stagedilated cardiomyopathy
What are the causes of low voltage ECG?

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QRS Complex
Professor DrMdToufiqurRahman
Fundamentals of ECG
Case 8: A 54 years old lady presented with chest heaviness with low
grade fever and palpitations for last 40 days. She has diabetes for last
15 years , now uncontrolled. She had the following ECG and her
echocardiogram report showed massive pericardial effusion.
Figure: Electrical alternans

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QRS Complex
Professor DrMdToufiqurRahman
Main Features to Consider
•Width of the complexes: Narrow
versus broad.
•Voltage (height) of the complexes.
•Spot diagnoses: Specific morphology
patterns that are important to
recognise.
Fundamentals of ECG

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QRS Complex naming convention
Professor DrMdToufiqurRahman
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
QRS Width
Normal QRS width is 70-100 ms(a duration of 110 msis
sometimes observed in healthy subjects). The QRS width
is useful in determining the origin of each QRS complex
(e.g. sinus, atrial, junctionalor ventricular).
Narrow complexes(QRS < 100 ms) aresupraventricularin origin.
Broad complexes(QRS > 100 ms) may be
eitherventricularin origin, or due toaberrant
conductionof supraventricular complexes (e.g. due to
bundle branch block, hyperkalaemiaor sodium-channel
blockade).
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
ECG showing both narrow and broad complexes
Sinus rhythm with frequent ventricular ectopic
beats(VEBs) in a pattern of ventricular bigeminy.
The narrow beats are sinus in origin, the broad
complexes are ventricular.
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Narrow QRS Complex Morphology
Narrow (supraventricular) complexes arise
from three main places:
Sino-atrial node (= normal P wave)
Atria (= abnormal P wave / flutter wave /
fibrillatorywave)
AV node / junction (= either no P wave or
an abnormal P wave with a PR interval <
120 ms)

Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Sinus rhythm: Each narrow complex is preceded by a normal P wave.
Atrial flutter: Narrow QRS complexes are associated with regular
flutter waves.
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Junctionaltachycardia: Narrow QRS complexes
with no visible P waves.
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Broad/Wide QRS Complexes
•A QRS duration > 100 msis abnormal
•A QRS duration > 120 msis required for the diagnosis of bundle
branch block or ventricular rhythm
•Broad complexes may be ventricular in origin or due to aberrant
conduction secondary to:
1.Bundle branch block (RBBBorLBBB)
2.Hyperkalaemia
3.Poisoning with sodium-channel blocking agents (e.g.tricyclic
antidepressants)
4.Pre-excitation(i.e. Wolff-Parkinson-White syndrome)
5.Ventricular pacing
6.Hypothermia
7.Intermittent aberrancy (e.g. rate-related aberrancy)
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Ventricular tachycardia: Broad QRS complexes with no visible P waves.
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Ventricular vssupraventricular rhythms
•Differentiation betweenventricularcomplexes
andaberrantly conductedsupraventricular complexes
may be difficult.
•In general, aberrant conduction of sinus rhythm and
atrial rhythms (tachycardia, flutter, fibrillation) can
usually be identified by the presence of preceding atrial
activity (P waves, flutter waves, fibrillatorywaves).
•However, aberrantly conducted junctional(AV nodal)
complexes may appear identical to ventricular complexes
as both produce broad QRSwithoutany preceding atrial
activity.
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Ventricular vssupraventricular rhythms
•In the case of ectopic beats, this distinction
is not really important (as occasional
ectopic beats do not usually require
treatment).
•However, in the case of sustained
tachyarrhythmias, the distinction between
ventricular tachycardia and SVT with
aberrancy becomes more important.
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
many causes of broad QRS can be identified by
pattern recognition:
RightbundlebranchblockproducesanRSR’
patterninV1anddeepslurredSwavesinthe
lateralleads.
LeftbundlebranchblockproducesadominantS
waveinV1withbroad,notchedRwavesand
absentQwavesinthelateralleads.
Hyperkalaemiaisassociatedwitharangeof
abnormalitiesincludingpeakedTwaves
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
many causes of broad QRS can be identified by
pattern recognition:
Tricyclicpoisoningisassociatedwithsinus
tachycardiaandtallR’waveinaVR
Wolff-ParkinsonWhitesyndromeischaracterised
byashortPRintervalanddeltawaves
Ventricularpacingwillusuallyhavevisiblepacing
spikes
Hypothermiaisassociatedwithbradycardia,long
QT,Osbornwavesandshiveringartefact
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
HighVoltageQRSMorphology
IncreasedQRSvoltageisoftentakentoinferthe
presenceofleftventricularhypertrophy.
However,highleftventricularvoltage(HLVV)maybea
normalfindinginpatientslessthan40-45yearsofage,
particularlyslimorathleticindividuals.
Therearemultiple“voltagecriteria”forleftventricular
hypertrophy.
ProbablythemostcommonlyusedaretheSokolov-Lyoncriteria(S
wavedepthinV1+tallestRwaveheightinV5-V6>35mm).
Voltagecriteriamustbeaccompaniedbynon-voltagecriteriatobe
considereddiagnosticofleftventricularhypertrophy.
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Low Voltage QRS Morphology
The QRS is said to below voltagewhen:
TheamplitudesofalltheQRS
complexesinthelimbleadsare<5
mm;or
TheamplitudesofalltheQRS
complexesintheprecordialleadsare<
10mm

Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Electrical Alternans
ThisiswhentheQRScomplexes
alternateinheight.
Themostimportantcauseismassive
pericardialeffusion,inwhichthe
alternatingQRSvoltageisduetothe
heartswingingbackandforthwithina
largefluid-filledpericardium.

Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Electrical Alternans
This is when the QRS complexes
alternate in height.
The most important cause ismassive
pericardial effusion, in which the
alternating QRS voltage is due to the
heart swinging back and forth within a
large fluid-filled pericardium.
Fundamentals of ECG

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QRS Complex
Professor DrMdToufiqurRahman
Spot Diagnoses
These cardiac diseases producedistinctive QRS
morphologiesthat are important not to miss:
Brugadasyndrome(partialRBBBwithST
elevationinV1-2)
Wolff-ParkinsonWhiteSyndrome(delta
wave)
Tricyclicpoisoning(wideQRSwith
dominantRwaveinaVR)
Fundamentals of ECG