ECG in

Detection Of

Chamber Enlargement

Cardiac Chamber Enlargement refers to:Cardiac Chamber Enlargement refers to:

- Dilatation of the heart chamber in which - Dilatation of the heart chamber in which the heart muscle is stretched and chamber the heart muscle is stretched and chamber

becomes enlarged.becomes enlarged.

- Hypertrophy in which the heart muscle - Hypertrophy in which the heart muscle fibers actually increase in size with fibers actually increase in size with resultant enlargement of chamber.resultant enlargement of chamber.

Cardiac Chamber Enlargement may occur due to Cardiac Chamber Enlargement may occur due to either increase in volume of blood within the either increase in volume of blood within the chamber termed volume overload or diastolic chamber termed volume overload or diastolic overload causing dilatation of the chamber.overload causing dilatation of the chamber.

An increase in resistance to blood flow out of it An increase in resistance to blood flow out of it termed pressure overload or systolic overload termed pressure overload or systolic overload causing thickness of myocardial wall of chamber.causing thickness of myocardial wall of chamber.

Indeed, Indeed, OverloadOverload rather than enlargement might be rather than enlargement might be more accurate term for ECG changes seen with more accurate term for ECG changes seen with enlargement because electrical effects may occur enlargement because electrical effects may occur before measurable dilatation or hypertrophy of before measurable dilatation or hypertrophy of affected chambers.affected chambers.

P WaveP Wave SA node initiates the activation of atrium.SA node initiates the activation of atrium. Since SA node is situated in right atrium, right atrial Since SA node is situated in right atrium, right atrial

activation begins first and is reflected by proximal or activation begins first and is reflected by proximal or ascending limb of P wave in frontal plane leads.ascending limb of P wave in frontal plane leads.

Duration of RA activation is 0.02 – 0.04 sec.Duration of RA activation is 0.02 – 0.04 sec. Left atrial activation begins 0.03 sec after right atrial Left atrial activation begins 0.03 sec after right atrial

activation and constitutes distal half or descending activation and constitutes distal half or descending limb of P wave.limb of P wave.

Duration of LA activation is 0.05 – 0.06 sec.Duration of LA activation is 0.05 – 0.06 sec. P wave is thus a composite deflection of right and P wave is thus a composite deflection of right and

left atrial activation.left atrial activation. Duration of P wave is 0.08 – 0.1 sec, max 0.11 sec. Duration of P wave is 0.08 – 0.1 sec, max 0.11 sec. Normal amplitude is 2.0mm, max 2.5mmNormal amplitude is 2.0mm, max 2.5mm

Fig 3.3 ShamratFig 3.3 Shamrat

The P wave in V1 is usually biphasic having initial The P wave in V1 is usually biphasic having initial positivity and terminal negativity. positivity and terminal negativity.

SA node is situated in RA and RA is situated SA node is situated in RA and RA is situated anteriorly and also is anterior to LA, the vector of RA anteriorly and also is anterior to LA, the vector of RA activation is thus directed anteriorly towards V1 activation is thus directed anteriorly towards V1 which records an initial positive deflection, 1.5mm in which records an initial positive deflection, 1.5mm in amplitude.amplitude.

Left atrial activation begins slightly later and the Left atrial activation begins slightly later and the vector is directed away from the lead V1 since LA is vector is directed away from the lead V1 since LA is situated posteriorly resulting in shallow negative situated posteriorly resulting in shallow negative deflection.deflection.

Duration of P wave in human is 0.05 sec and not Duration of P wave in human is 0.05 sec and not more than 0.08 sec.more than 0.08 sec.

Terminal negative deflection is normally not Terminal negative deflection is normally not exceeding 1mm in depth and 0.03 sec in duration. exceeding 1mm in depth and 0.03 sec in duration.

Normal P wave is always negative in AVR and Normal P wave is always negative in AVR and positive in lead II.positive in lead II.

Atrial depolarisation path spreads from right to left Atrial depolarisation path spreads from right to left and downwards towards atrioventricular junction and and downwards towards atrioventricular junction and therefore towards the positive pole of lead II and therefore towards the positive pole of lead II and away from the positive pole of AVR.away from the positive pole of AVR.

Therefore, normal frontal plane of P wave axis is in Therefore, normal frontal plane of P wave axis is in the region of +45the region of +4500 to +65 to +6500..

P wave axis more than 70P wave axis more than 7000 results in right axis results in right axis deviation and less than 45deviation and less than 4500 results in left axis results in left axis deviation.deviation.

Normal P wave

Normal P wave is thus:Normal P wave is thus: Always positive in lead II and negative in lead AVR.Always positive in lead II and negative in lead AVR. Duration in lead II is 0.08 – 0.1 sec max. 0.11 sec.Duration in lead II is 0.08 – 0.1 sec max. 0.11 sec. Amplitude in lead II: Usually 2mm max. 2.5 mmAmplitude in lead II: Usually 2mm max. 2.5 mm Lead V1: Usually biphasicLead V1: Usually biphasic

# Initial positive deflection < 1.5mm in amplitude# Initial positive deflection < 1.5mm in amplitude

# Terminal negative deflection not exceeding # Terminal negative deflection not exceeding 1mm in depth and < 0.03 sec in duration. 1mm in depth and < 0.03 sec in duration.

# Duration of P wave in V1 is 0.05 – 0.08 sec.# Duration of P wave in V1 is 0.05 – 0.08 sec. P wave axis in frontal plane: +45P wave axis in frontal plane: +4500 to +65 to +6500

> 70> 7000 – right axis – right axis

< 45< 4500 – left axis – left axis

Genesis of QRS ComplexGenesis of QRS Complex Activation of ventricles begin in left sub-endocardial Activation of ventricles begin in left sub-endocardial

region of lower 1/3region of lower 1/3rdrd of IVS spreading transversely from of IVS spreading transversely from left to right, sometimes referred as septal force or septal left to right, sometimes referred as septal force or septal vector.vector.

Activation of IVS is followed by activation of free wall of Activation of IVS is followed by activation of free wall of both ventricles transversely from endocardial to both ventricles transversely from endocardial to epicardial region.epicardial region.

The large right to left force of free wall of LV will The large right to left force of free wall of LV will dominate and counteracts the smaller left to right force dominate and counteracts the smaller left to right force of free wall of RV resulting in an effective or net resultant of free wall of RV resulting in an effective or net resultant vector which is directed from right to left through free vector which is directed from right to left through free wall of LV.wall of LV.

Thus the activation of ventricals may be depicted as a Thus the activation of ventricals may be depicted as a small initial vector from left to right through IVS followed small initial vector from left to right through IVS followed by large vector from right to left through free wall of LV. by large vector from right to left through free wall of LV.

Diagram illustrating various forms of QRS deflection Diagram illustrating various forms of QRS deflection and their nomenclature.and their nomenclature.

Normal VATNormal VAT

VAT is the time from the onset of QRS complex to VAT is the time from the onset of QRS complex to maximum height of R wave or the time of onset of maximum height of R wave or the time of onset of intrinsicoid deflection i.e. the downstroke of QRS.intrinsicoid deflection i.e. the downstroke of QRS.

VAT is most important in left oriented leads since it VAT is most important in left oriented leads since it indirectly reflects the transverse conduction time of free indirectly reflects the transverse conduction time of free wall of LV. wall of LV. Ex: Ex: VAT may be prolonged in LVH, LAHB, VAT may be prolonged in LVH, LAHB, LBBB LBBB

Frontal plane of QRS axisFrontal plane of QRS axis

Mean QRS axis lies between -30 to +90Mean QRS axis lies between -30 to +9000.. Mean QRS axis more than +90Mean QRS axis more than +9000 – Rt. axis deviation. – Rt. axis deviation. Mean QRS axis more than -30Mean QRS axis more than -3000 – Lt. axis deviation. – Lt. axis deviation.

Most normal QRS complex in the adult is Most normal QRS complex in the adult is within the narrow range between +40within the narrow range between +4000 to +60 to +6000. .

Normal QRS

Normal QRSNormal QRS Normal mean frontal plane QRS is in the region of +40Normal mean frontal plane QRS is in the region of +4000 to to

+60+6000 towards positive pole of lead II. Therefore ,QRS is towards positive pole of lead II. Therefore ,QRS is usually largest in lead II.usually largest in lead II.

Normal frontal plane QRS axis is usually directed inferiorly Normal frontal plane QRS axis is usually directed inferiorly and to left and to negative pole of AVR. Therefore and to left and to negative pole of AVR. Therefore reflecting complete negativity of QRS complex in AVR.reflecting complete negativity of QRS complex in AVR.

QRS duration: 0.05 – 0.11 secQRS duration: 0.05 – 0.11 sec Normal Q wave does not exceed 0.03 sec, most frequently Normal Q wave does not exceed 0.03 sec, most frequently

0.01 sec in duration and 0.5mm in magnitude.0.01 sec in duration and 0.5mm in magnitude. Leads oriented to RV reflects rS complex and that of LV Leads oriented to RV reflects rS complex and that of LV

reflects qR complex.reflects qR complex. The transition zone from rS to qR complex most commonly The transition zone from rS to qR complex most commonly

manifests in lead V3.manifests in lead V3. VAT: Right oriented leads 0.02 sec, left oriented leads 0.04 VAT: Right oriented leads 0.02 sec, left oriented leads 0.04

sec.sec.

Right Atrial Enlargement (RAE)Right Atrial Enlargement (RAE) 1) Many diseases of 1) Many diseases of

right side of the heart right side of the heart are associated with are associated with EGC abnormalities.EGC abnormalities.

2) The ECG changes 2) The ECG changes suggesting RAE often suggesting RAE often correlates poorly with correlates poorly with clinical and clinical and pathological findings.pathological findings.

Differential Diagnosis of RAEDifferential Diagnosis of RAE Valvular Diseases:Valvular Diseases: Tricuspid stenosis Tricuspid stenosis

Tricuspid RegurgitationTricuspid Regurgitation Pulmonary Hypertension:Pulmonary Hypertension:

COPDCOPD Pulmonary EmbolismPulmonary Embolism Interstitial Lung diseaseInterstitial Lung disease Sleep ApneaSleep Apnea Mitral valve diseaseMitral valve disease LV Systolic dysfunctionLV Systolic dysfunction

Congenital Heart Disease(CHD):Congenital Heart Disease(CHD): Pulmonary Stenosis Pulmonary Stenosis

Tetralogy of FellotTetralogy of Fellot Ebstein’s AnamolyEbstein’s Anamoly

In practice, most cases RAE are associated with RVH.In practice, most cases RAE are associated with RVH. ECG features of RAE without RVH seen in TS.ECG features of RAE without RVH seen in TS. P Pulmonale may appear transiently in acute pulmonary embolism and P Pulmonale may appear transiently in acute pulmonary embolism and

status asthamaticus.status asthamaticus.

ECG Diagnosis of RAEECG Diagnosis of RAE Abnormalities of P waveAbnormalities of P wave: The P wave amplitude is : The P wave amplitude is

increased so that it exceeds 2.5mm. It is seen best increased so that it exceeds 2.5mm. It is seen best in standard lead II.in standard lead II.

If there is a right axis deviation of P wave as If there is a right axis deviation of P wave as commonly occurs in COPD, the tall P wave will be commonly occurs in COPD, the tall P wave will be seen in II, III, AVF.seen in II, III, AVF.

The total duration of P wave remains normal.The total duration of P wave remains normal.

Increase in amplitude of the initial P wave deflection Increase in amplitude of the initial P wave deflection in lead V1.in lead V1.

With RAE initial deflection of P wave in V1 becomes With RAE initial deflection of P wave in V1 becomes taller and amplitude will exceed > 1.5 mm.taller and amplitude will exceed > 1.5 mm.

The right atrial component of the wave may also The right atrial component of the wave may also increase in duration > 0.04 sec and this is a very increase in duration > 0.04 sec and this is a very sensitive indicator.sensitive indicator.

The frontal plane axis of P wave in various The frontal plane axis of P wave in various conditionsconditions

A.A. Normal axis +40Normal axis +4000 to +60 to +6000..B.B. Rightward directed P wave axis. Mirror image Rightward directed P wave axis. Mirror image

dextrocardia or reversed arm electrodes.dextrocardia or reversed arm electrodes.C.C. P wave associated with LAE +45P wave associated with LAE +4500 to -30 to -3000..D.D. P wave associated with CHD, termed P congenital -P wave associated with CHD, termed P congenital -

404000 to -70 to -7000. Leftward deviation of tall and peaked P . Leftward deviation of tall and peaked P wave is associated with Toff and isolated PS. Marked wave is associated with Toff and isolated PS. Marked leftward deviation occurs in Ebsteins anamoly.leftward deviation occurs in Ebsteins anamoly.

E.E. P pulmonale in COPD commonly directed to +90P pulmonale in COPD commonly directed to +9000 and and this results in small equiphasic complex in standard this results in small equiphasic complex in standard lead I.lead I.

F.F. P axis in the region of -80 to -90, a PP axis in the region of -80 to -90, a P II wave due to wave due to retrograde activation of atria from impulse originating retrograde activation of atria from impulse originating from AV node.from AV node.

G.G. PPII wave of WPW syndrome retrograde conduction wave of WPW syndrome retrograde conduction through left sided bypass of WPW syndrome.through left sided bypass of WPW syndrome.

RAE is sometimes RAE is sometimes manifest with terminal manifest with terminal negativity in lead V1 but negativity in lead V1 but intrinscicoid deflection will intrinscicoid deflection will not exceed 0.03 sec, not exceed 0.03 sec, unlike in LAE where it is unlike in LAE where it is more than 0.03 sec.more than 0.03 sec.

The negative deflection in The negative deflection in V1 with RAE is V1 with RAE is associated tall and associated tall and pointed P wave in V2.pointed P wave in V2.

Abnormalities of QRS complex reflecting RAEAbnormalities of QRS complex reflecting RAE

The QRS complex in V1 is an indirect sign of RAE and is The QRS complex in V1 is an indirect sign of RAE and is usually due to Tricuspid Regurgitation. The tall R wave is an usually due to Tricuspid Regurgitation. The tall R wave is an expression of RVH and the initial small Q wave is due to expression of RVH and the initial small Q wave is due to result of anatomical shift of heart due to RAE.result of anatomical shift of heart due to RAE.

RAE: Peaked P wave in II, III AVFRAE: Peaked P wave in II, III AVF Positive P wave in V1.Positive P wave in V1. Marked increase in QRS amplitude from V1 to V2.Marked increase in QRS amplitude from V1 to V2.

RVH: Right axis deviation + 140.RVH: Right axis deviation + 140. S1, S2, S3 pattern S1, S2, S3 pattern

Diminution in size of QRS deflection in V1 with marked Diminution in size of QRS deflection in V1 with marked increase in QRS amplitude in V2 is attributed to large increase in QRS amplitude in V2 is attributed to large volume of blood in RA that lies between ventricle and volume of blood in RA that lies between ventricle and precordial electrodes. precordial electrodes.

Diagnostic accuracy of RAEDiagnostic accuracy of RAE The finding of RAE has limited sensitivity but high The finding of RAE has limited sensitivity but high

specificity.specificity. If correlated Echocardiographically, P pulmonale has If correlated Echocardiographically, P pulmonale has

very low sensitivity but very high specificity for detecting very low sensitivity but very high specificity for detecting RAE. RAE.

Left Atrial Enlargement (LAE)Left Atrial Enlargement (LAE)

Differential DiagnosisDifferential Diagnosis Valvular disease Valvular disease

Mitral stenosis Mitral stenosis Mitral regurgitation Mitral regurgitation

  Decreased Left Ventricular Compliance Decreased Left Ventricular Compliance Longstanding hypertension Longstanding hypertension Obstructive cardiomyopathy Obstructive cardiomyopathy Aortic stenosis Aortic stenosis Aortic regurgitation Aortic regurgitation Infiltrative heart disease Infiltrative heart disease

All of these conditions increase either pressure or All of these conditions increase either pressure or volume loading on the atria leading to enlargement volume loading on the atria leading to enlargement and/or hypertrophy. and/or hypertrophy.

LAE results in 3 basic ECG changes:LAE results in 3 basic ECG changes:

1.1. Prolongation and delay of the terminal or left atrial Prolongation and delay of the terminal or left atrial component of atrial activation.component of atrial activation.

2.2. Increased posterior deviation of left atrial vector.Increased posterior deviation of left atrial vector.

3.3. Left axis deviation of mean manifest frontal plane Left axis deviation of mean manifest frontal plane P wave axis.P wave axis.

Prolongation and delay of Left atrial component Prolongation and delay of Left atrial component of Atrial activationof Atrial activation

• P wave is prolonged due to delay in left atrial or terminal component and manifests in lead II.

• When there is left axis deviation of P wave, the features manifests in I and AVL.

• P wave shows double peaked or camel hump.

• Duration of P wave is longer than 0.11 sec.

• Distance between camel hump is > 0.04 sec.

Increased Posterior deviation of Left Atrial VectorIncreased Posterior deviation of Left Atrial Vector

Left atrial component of atrial activation is prolonged, Left atrial component of atrial activation is prolonged, increased in magnitude and directed further posteriorly and increased in magnitude and directed further posteriorly and away from lead V1, thus lead V1 reflects relatively deep, away from lead V1, thus lead V1 reflects relatively deep, delayed and widened terminal negative component. delayed and widened terminal negative component.

Morris IndexMorris Index Also known as P terminal force.Also known as P terminal force. This measurement is the evaluation of terminal This measurement is the evaluation of terminal

negative component of P wave in lead V1.negative component of P wave in lead V1. This is derived from multiplying the depth of terminal This is derived from multiplying the depth of terminal

P wave deflection in P wave deflection in mm mm by duration in by duration in sec sec and and expressed in expressed in mm secmm sec..

Normally the depth of terminal P wave is 1mm and Normally the depth of terminal P wave is 1mm and duration is 0.03 sec.duration is 0.03 sec.

The P terminal force is 1x 0.03 = 0.03 mm sec.The P terminal force is 1x 0.03 = 0.03 mm sec. If the P terminal force exceeds 0.03 mm sec, it If the P terminal force exceeds 0.03 mm sec, it

constitutes LAE.constitutes LAE.

Diagnostic AccuracyDiagnostic Accuracy Diagnostic accuracy of these LAE criteria are Diagnostic accuracy of these LAE criteria are

limited.limited. Comparing to Echocardiographic criteria for LAE, Comparing to Echocardiographic criteria for LAE,

ECG has limited sensitivity of 20% but specificity of ECG has limited sensitivity of 20% but specificity of 98% for classic P mitrale pattern.98% for classic P mitrale pattern.

Because of the correlation of these ECG features Because of the correlation of these ECG features with high atrial pressure, intra atrial conduction with high atrial pressure, intra atrial conduction defects and ventricular dysfunction, as well as defects and ventricular dysfunction, as well as increased atrial size, these ECG abnormalities are increased atrial size, these ECG abnormalities are preferably referred to as criteria for LA abnormality preferably referred to as criteria for LA abnormality rather than LAE.rather than LAE.

Left Atrial EnlargementLeft Atrial Enlargement::

- Wide notched P waves in I AVL, V4-V6.- Wide notched P waves in I AVL, V4-V6.

- P wave duration prolonged > 0.13 sec- P wave duration prolonged > 0.13 sec

- Duration of notch of P wave > 0.07 sec- Duration of notch of P wave > 0.07 sec

- Depth of P in V1 > 4mm, duration > 0.08 sec- Depth of P in V1 > 4mm, duration > 0.08 sec

- Morris index is 4mm X 0.08 sec = 0.32mm sec - Morris index is 4mm X 0.08 sec = 0.32mm sec LV Diastolic overloadLV Diastolic overload

Biatrial EnlargementBiatrial Enlargement Because P wave composed of distinct right and left Because P wave composed of distinct right and left

atrial components, the diagnosis of biatrial atrial components, the diagnosis of biatrial enlargement is simply made by looking for criteria enlargement is simply made by looking for criteria for both left and right atrial enlargement.for both left and right atrial enlargement.

Large biphasic P wave in V1 with initial component Large biphasic P wave in V1 with initial component greater than 1.5 mm in height and terminal greater than 1.5 mm in height and terminal component atleast 1 mm in depth and 0.04 sec in component atleast 1 mm in depth and 0.04 sec in duration.duration.

A P wave amplitude of more than 2.5 mm and A P wave amplitude of more than 2.5 mm and duration of more than 0.12 sec in lead II.duration of more than 0.12 sec in lead II.

Biatrial EnlargementBiatrial Enlargement: : LAE: - Wide notched P waves in all frontal plane LAE: - Wide notched P waves in all frontal plane

leads and V4 – V6.leads and V4 – V6.

- P terminal force in V1 is - P terminal force in V1 is

1.5mm X 0.04sec = 0.06mm sec.1.5mm X 0.04sec = 0.06mm sec. RAE: - Relatively large amplitude of initial P wave RAE: - Relatively large amplitude of initial P wave

deflection in frontal plane leads.deflection in frontal plane leads.

- Tall peaked P wave in V2, V3.- Tall peaked P wave in V2, V3. LV diastolic Overload. LV diastolic Overload.

LAE: - Wide notched P wave in standard leads and V4 – V6. P LAE: - Wide notched P wave in standard leads and V4 – V6. P wave in II is > 0.12 sec. wave in II is > 0.12 sec.

- P terminal force in V1 is 2mm X 0.06 sec = 0.12mm sec.- P terminal force in V1 is 2mm X 0.06 sec = 0.12mm sec. RAE: - Tall initial component of P wave in II, III AVF, amplitude of RAE: - Tall initial component of P wave in II, III AVF, amplitude of

P wave in II is 5mm. P wave in II is 5mm. - Small initial q wave in V1 of qR complex.- Small initial q wave in V1 of qR complex. - P wave axis is + 60 shows the balancing effect of RAE - P wave axis is + 60 shows the balancing effect of RAE

and and LAE. LAE. RV Enlargement: Right axis deviation, Tall R in V1, T inversion in RV Enlargement: Right axis deviation, Tall R in V1, T inversion in

V1 – V4, rS complex in V2 – V6.V1 – V4, rS complex in V2 – V6. RAE, Rt axis deviation, clockwise rotation reflects development of RAE, Rt axis deviation, clockwise rotation reflects development of

PH.PH.

Differential Diagnosis of Biatrial Differential Diagnosis of Biatrial EnlargementEnlargement

Mitral stenosis with pulmonary hypertension.Mitral stenosis with pulmonary hypertension. Mitral stenosis with Tricuspid Regurgitation.Mitral stenosis with Tricuspid Regurgitation. Mitral stenosis with Tricuspid Stenosis.Mitral stenosis with Tricuspid Stenosis. Atrial septal defect.Atrial septal defect. Luten Backers syndrome.Luten Backers syndrome.

Right Ventricular Hypertrophy and Right Ventricular Hypertrophy and EnlargementEnlargement

The forces generated by right ventricular The forces generated by right ventricular depolarization are directed rightwards and anteriorly depolarization are directed rightwards and anteriorly and almost completely masked by dominant forces and almost completely masked by dominant forces of left ventricular depolarization.of left ventricular depolarization.

In the presence of RVH the forces of depolarization In the presence of RVH the forces of depolarization increase, and if hypertrophy is severe these forces increase, and if hypertrophy is severe these forces may dominate on ECG.may dominate on ECG.

ECG is relatively insensitive indicator of the ECG is relatively insensitive indicator of the presence of RVH and in the mild cases of RVH the presence of RVH and in the mild cases of RVH the ECG will be ECG will be normalnormal..

Differential Diagnosis of RVHDifferential Diagnosis of RVH Pulmonary stenosis Pulmonary stenosis Mitral stenosisMitral stenosis Ventricular Septal DefectVentricular Septal Defect Atrial Septal DefectAtrial Septal Defect Pulmonary HypertensionPulmonary Hypertension

* COPD* COPD

* Pulmonary Embolism* Pulmonary Embolism

* Sleep Apnea* Sleep Apnea

* Interstitial Lung Disease* Interstitial Lung Disease

Basic ECG presentation of RVHBasic ECG presentation of RVH Right axis deviation is the commonest and at times Right axis deviation is the commonest and at times

only presentation usually directed from only presentation usually directed from

+90+9000 to +180 to +18000.. Such right axis deviation is usually an expression of Such right axis deviation is usually an expression of

free right wall hypertrophy.free right wall hypertrophy. When hypertrophy of basal region of the RV When hypertrophy of basal region of the RV

predominates the frontal plane QRS deviates even predominates the frontal plane QRS deviates even further to the right superior Quadrant the northwest further to the right superior Quadrant the northwest region and occurs in - Toffregion and occurs in - Toff

- Transposition complexes- Transposition complexes

- Severe Isolated PS- Severe Isolated PS

Severe Pulmonary StenosisSevere Pulmonary Stenosis RAE: - Tall and peaked P wave in I, II V1 – V6.RAE: - Tall and peaked P wave in I, II V1 – V6.

- Positive P wave in V1.- Positive P wave in V1.

- First degree AV block – prolong PR interval.- First degree AV block – prolong PR interval. RVH: - Tall R wave in V1 > 25mm, no S wave.RVH: - Tall R wave in V1 > 25mm, no S wave.

- RS complex in V2 – V6.- RS complex in V2 – V6.

- Right axis deviation of QRS complex + 170.- Right axis deviation of QRS complex + 170.

- Deeply inverted and sharply pointed T waves in RV leads. - Deeply inverted and sharply pointed T waves in RV leads.

Tetrology of Fallot Tetrology of Fallot RAE: - Tall and peak P wave in II, III AVF.RAE: - Tall and peak P wave in II, III AVF.

- Tall and peak P wave in V1.- Tall and peak P wave in V1.

- Marked increase in QRS magnitude in V1-V2- Marked increase in QRS magnitude in V1-V2

- Small initial q wave of qRs complex in V1.- Small initial q wave of qRs complex in V1. RVH: - Tall R of qRs complex in V1 and inverted T RVH: - Tall R of qRs complex in V1 and inverted T wave. wave.

- Clockwise rotation- Clockwise rotation

- Right axis deviation + 140- Right axis deviation + 140

Differential Diagnosis of Right axis Differential Diagnosis of Right axis DeviationDeviation

Right Ventricular HypertrophyRight Ventricular Hypertrophy Left posterior HemiblockLeft posterior Hemiblock Anteriolateral myocardial infarctionAnteriolateral myocardial infarction Acute Right Heart Strain Acute Right Heart Strain

Dominance of R wave in Right Oriented Dominance of R wave in Right Oriented LeadsLeads

With increasing RVH, the R wave in the right With increasing RVH, the R wave in the right oriented leads becomes increasingly dominant oriented leads becomes increasingly dominant specially in V1 with progressive diminution of S specially in V1 with progressive diminution of S wave. wave.

This is often expressed as a R:S ratio or RThis is often expressed as a R:S ratio or R II:S ratio :S ratio and if this ratio is > 1 the presence of RVH can and if this ratio is > 1 the presence of RVH can usually be diagnosed and this carries an increased usually be diagnosed and this carries an increased significance if R or Rsignificance if R or RII wave is greater than 5 mm in wave is greater than 5 mm in amplitude. amplitude.

Differential Diagnosis of tall R in V1Differential Diagnosis of tall R in V1 Right Ventricular Hypertrophy Right Ventricular Hypertrophy Posterior wall MI.Posterior wall MI. Type A WPW syndromeType A WPW syndrome RBBBRBBB

qR complex in lead V1qR complex in lead V1 Small q wave with ensuing tall R wave in lead V1 Small q wave with ensuing tall R wave in lead V1

reflects RVH with RAE. reflects RVH with RAE. The tall R wave is an expression of RVH and small q The tall R wave is an expression of RVH and small q

wave indirectly reflects RAE.wave indirectly reflects RAE. This qR pattern is due to an anatomical shift of This qR pattern is due to an anatomical shift of

hypertrophid RV by dilated RA.hypertrophid RV by dilated RA.

Mitral Stenosis + Tricuspid StenosisMitral Stenosis + Tricuspid Stenosis LAE: - Wide notched P wave in II, III, AVF, V2 – V6.LAE: - Wide notched P wave in II, III, AVF, V2 – V6.

- P terminal force 3 X 0.08 = 0.24mm sec.- P terminal force 3 X 0.08 = 0.24mm sec. RAE: - Tall and volcano like P waves in I, II, AVF, V3 – V6.RAE: - Tall and volcano like P waves in I, II, AVF, V3 – V6.

- qR in V1also connotes RAE.- qR in V1also connotes RAE.

- First degree AV block - PR interval 0.22 sec. - First degree AV block - PR interval 0.22 sec. RVH: - Tall R wave in V1 – V2 right axis deviation, RVH: - Tall R wave in V1 – V2 right axis deviation,

clockwise rotation. RVH reflects PH. clockwise rotation. RVH reflects PH. Very tall wide and notched P wave are characteristically Very tall wide and notched P wave are characteristically

associated with Tricuspid Stenosis. associated with Tricuspid Stenosis.

Increase in Ventricular Activation Time Increase in Ventricular Activation Time (VAT)(VAT)

VAT normally does not exceed 0.02 sec in lead V1.VAT normally does not exceed 0.02 sec in lead V1. VAT > 0.02 sec constitutes significant evidence of VAT > 0.02 sec constitutes significant evidence of

free wall of Right ventricular hypertrophy provided free wall of Right ventricular hypertrophy provided there is no RBBB. there is no RBBB.

Increase in VAT is due to increased time the Increase in VAT is due to increased time the activation front takes to travel transversely through activation front takes to travel transversely through hypertrophied free RV wall.hypertrophied free RV wall.

RS or rS complexes in left oriented leadsRS or rS complexes in left oriented leads This is an expression of diminishing R wave and This is an expression of diminishing R wave and

increasing S wave which reflects increasing increasing S wave which reflects increasing dominance of right oriented forces.dominance of right oriented forces.

A QRS complex with an S wave of greater A QRS complex with an S wave of greater magnitude than the R wave is particularly indicative magnitude than the R wave is particularly indicative of RVH.of RVH.

Clockwise electrical rotation around Clockwise electrical rotation around longitudinal axislongitudinal axis

Clockwise rotation is the expression of right Clockwise rotation is the expression of right ventricular QRS forces which are increased in ventricular QRS forces which are increased in magnitude and directed more anteriorly.magnitude and directed more anteriorly.

The transition zone is shifted to the left and may be The transition zone is shifted to the left and may be evident in leads V4, V5 and V6. evident in leads V4, V5 and V6.

Pulmonary StenosisPulmonary Stenosis RAE: - Tall and peak P wave in I, II, V1 – V6.RAE: - Tall and peak P wave in I, II, V1 – V6.

- Positive P in V1, no negative component- Positive P in V1, no negative component RVH: - Very tall R wave in V1, 25mmRVH: - Very tall R wave in V1, 25mm

- Very tall R wave of RS complex V2 – V4. This is expression - Very tall R wave of RS complex V2 – V4. This is expression of of right paraseptal ventricular hypertrophy. right paraseptal ventricular hypertrophy.

- Marked clockwise rotation.- Marked clockwise rotation.

- Right axis Deviation + 170- Right axis Deviation + 170

- Deeply inverted sharply pointed T waves in RV leads.- Deeply inverted sharply pointed T waves in RV leads.

Hypertrophy predominently the basal region Hypertrophy predominently the basal region of the RVof the RV

The basal QRS forces dominate and directed The basal QRS forces dominate and directed superiorly to right and somewhat posteriorly away superiorly to right and somewhat posteriorly away from V1 or V2 reflecting dominantly negative or rS from V1 or V2 reflecting dominantly negative or rS complex.complex.

Lead V5, V6 also reflects deep S wave or rS Lead V5, V6 also reflects deep S wave or rS complex. complex.

AVR will reflect a tall R wave of a qR complex since AVR will reflect a tall R wave of a qR complex since these vectors are directed to lead AVR. these vectors are directed to lead AVR.

There may be terminal S waves in all three standard There may be terminal S waves in all three standard leads the S1, S2, S3 syndrome.leads the S1, S2, S3 syndrome.

The frontal plane QRS axis is in the right superior or The frontal plane QRS axis is in the right superior or NorthWest region. NorthWest region.

Differential diagnosis of frontal plane NW region:Differential diagnosis of frontal plane NW region:

RVH + LAHBRVH + LAHB

ToffToff

ASD, VSD, PS ASD, VSD, PS

ST segment and T waveST segment and T wave When RV is under strain due to increased right When RV is under strain due to increased right

intraventricular pressure, the T wave vector is directed intraventricular pressure, the T wave vector is directed away from the right resulting in T wave inversion in away from the right resulting in T wave inversion in right oriented leads V1 – V4. right oriented leads V1 – V4.

The T wave inversion is usually most marked in V1 The T wave inversion is usually most marked in V1 and V2 and diminishes progressively in amplitude to and V2 and diminishes progressively in amplitude to right.right.

With severe compromise of the RV as in severe PS, With severe compromise of the RV as in severe PS, the inverted T wave may be very deep, symmetrical the inverted T wave may be very deep, symmetrical and pointed – tend to ischemic in type. and pointed – tend to ischemic in type.

ST segment is minimally depressed and slightly ST segment is minimally depressed and slightly convex upwards.convex upwards.

The frontal plane T wave axis is directed to left The frontal plane T wave axis is directed to left superior quadrant and associated with right QRS axis superior quadrant and associated with right QRS axis resulting in wide QRS – T angle.resulting in wide QRS – T angle.

RV Diastolic OverloadRV Diastolic Overload

RV Diastolic OverloadRV Diastolic Overload RV diastolic overload occurs when there is RV diastolic overload occurs when there is

excessive filling of RV during diastole.excessive filling of RV during diastole.Ex:Ex: ASD ASD

The ECG presentation is that of incomplete or The ECG presentation is that of incomplete or complete RBBB, rSRcomplete RBBB, rSRII deflection. deflection.

Differential diagnosis of RBBB:Differential diagnosis of RBBB:- Normal Variant- Normal Variant- Coronary Artery Disease- Coronary Artery Disease- Various Cardiomyopathies- Various Cardiomyopathies- Ebsteins anamoly- Ebsteins anamoly- ASD- ASD- Acute Pulmonary embolism- Acute Pulmonary embolism

SummarySummary General ECG features:General ECG features: SensitivitySensitivity SpecificitySpecificity

- Right axis deviation > 90- Right axis deviation > 9000 14 14 99 99

- Tall R in RV leads > 7 mm- Tall R in RV leads > 7 mm 10 10

- Deep S in LV leads- Deep S in LV leads

- Slight increase in QRS duration- Slight increase in QRS duration

- ST-T changes - ST-T changes

- S1, S2, S3 pattern- S1, S2, S3 pattern 10 10

- Incomplete RBBB or qR in V1- Incomplete RBBB or qR in V1

- Evidence of RAE P Pulmonale - Evidence of RAE P Pulmonale 11%11%

Specific ECG features:Specific ECG features:

- Any one or more of the following:- Any one or more of the following:

- Right axis deviation- Right axis deviation

- R in AVR > 5mm- R in AVR > 5mm

- R in AVR > Q in AVR- R in AVR > Q in AVR

- Any one of the following in V1:- Any one of the following in V1:

- R/S ratio > 1 and –ve T wave 25 - R/S ratio > 1 and –ve T wave 25 8989

- qR pattern- qR pattern 1010

- R > 6mm or S < 2mm- R > 6mm or S < 2mm

- rSR- rSRII with R with RII > 10 mm > 10 mm

Other Chest Lead Criteria:Other Chest Lead Criteria:

- R in V1 + S in V5 (or V6) 10mm- R in V1 + S in V5 (or V6) 10mm

- R/S ratio in V5 or V6 < 1- R/S ratio in V5 or V6 < 1 10 9310 93

- R in V5 or V6 < 5mm- R in V5 or V6 < 5mm 1010

- S in V5 or V6 > 7mm- S in V5 or V6 > 7mm 17 9317 93 ST depression and T wave inversion in right precordial ST depression and T wave inversion in right precordial

leads is usually seen in severe RVH such as PS, PH.leads is usually seen in severe RVH such as PS, PH. Buttler-Leggett formula for RVHButtler-Leggett formula for RVH

tallest R or R’ in lead V1or V2 -Anterior direction tallest R or R’ in lead V1or V2 -Anterior direction

deepest S in lead 1 or V6 -Rightward directiondeepest S in lead 1 or V6 -Rightward direction

S in lead V1 - Posterior-leftward directionS in lead V1 - Posterior-leftward direction

RVH=A+R-PL>=7mm.RVH=A+R-PL>=7mm.

Example #1:Example #1: (note RAD +105 degrees; RAE; R in V1 (note RAD +105 degrees; RAE; R in V1 > 6 mm; R in aVR > 5 mm) > 6 mm; R in aVR > 5 mm)

Example #2:Example #2: (more subtle RVH: note RAD +100 (more subtle RVH: note RAD +100 degrees; RAE; Qr complex in V1 rather than qR is degrees; RAE; Qr complex in V1 rather than qR is atypical) atypical)

Example #3:Example #3: (note: RAD +120 degrees, qR in V1; (note: RAD +120 degrees, qR in V1; R/S ratio in V6 <1) R/S ratio in V6 <1)

Large P waves in leads II, III, and aVF Large P waves in leads II, III, and aVF

(P pulmonale)(P pulmonale)

Right ventricular hypertrophy secondary to Right ventricular hypertrophy secondary to pulmonary stenosis (note the dominant R wave in pulmonary stenosis (note the dominant R wave in lead V1, presence of right atrial hypertrophy, right lead V1, presence of right atrial hypertrophy, right axis deviation, and T wave inversion in leads V1 to axis deviation, and T wave inversion in leads V1 to V3)V3)

Chronic obstructive pulmonary disease (note the P Chronic obstructive pulmonary disease (note the P pulmonale, low amplitude QRS complexes, and poor pulmonale, low amplitude QRS complexes, and poor R wave progression)R wave progression)

Sinus tachycardia and S1, Q3, T3 pattern in Sinus tachycardia and S1, Q3, T3 pattern in patient with pulmonary emboluspatient with pulmonary embolus

S1, Q3, T3 pattern and right bundle branch block in S1, Q3, T3 pattern and right bundle branch block in patient with pulmonary emboluspatient with pulmonary embolus

Acute pulmonary embolism: (note the T wave Acute pulmonary embolism: (note the T wave inversion in the right precordial leads and lead III)inversion in the right precordial leads and lead III)

Left Ventricular Hypertrophy (LVH)Left Ventricular Hypertrophy (LVH)

The S wave of right oriented leads and R wave of left The S wave of right oriented leads and R wave of left oriented leads represent the dominant right to left QRS oriented leads represent the dominant right to left QRS vector of ventricular depolarization.vector of ventricular depolarization.

LVH may occur as a result of 2 basic haemodynamic LVH may occur as a result of 2 basic haemodynamic abnormalities:abnormalities:1.1. Systolic overload or pressure overload, expression Systolic overload or pressure overload, expression of resistance to LV systolic outflow.of resistance to LV systolic outflow.

Aortic stenosisAortic stenosisHypertensionHypertensionHypertrophic CardioMyopathy (HCM)Hypertrophic CardioMyopathy (HCM)Coarctation of AortaCoarctation of Aorta

2. Diastolic overload or volume overload due to 2. Diastolic overload or volume overload due to overfilling of LV in diastole.overfilling of LV in diastole.

Mitral Regurgitation (MR)Mitral Regurgitation (MR)Aortic Regurgitation (AR)Aortic Regurgitation (AR)Left to Right shunt PDA, VSDLeft to Right shunt PDA, VSD

Abnormalities of QRS complexAbnormalities of QRS complex

1)1) Increase in magnitude of QRS deflection:Increase in magnitude of QRS deflection:

- LVH results in deep S wave in RV leads and- LVH results in deep S wave in RV leads and

tall R wave in LV leads and if in an adult with tall R wave in LV leads and if in an adult with normal chest built the sum of two deflections normal chest built the sum of two deflections exceeds 35 mm it constitutes LVH. exceeds 35 mm it constitutes LVH.

- Normally R wave in V5 is taller than V6, if R in V6 - Normally R wave in V5 is taller than V6, if R in V6 equals or exceeds R in V5 it also indicates LVH.equals or exceeds R in V5 it also indicates LVH.

- R wave in lead I > 15 mm.- R wave in lead I > 15 mm.

- R wave in AVL > 11 mm with concomitant left QRS - R wave in AVL > 11 mm with concomitant left QRS axis.axis.

2)2) Attenuation of small initial Q wave in left oriented Attenuation of small initial Q wave in left oriented leads, it reflects the development of incomplete leads, it reflects the development of incomplete LBBB and is probably due to increased pressure LBBB and is probably due to increased pressure on IVS.on IVS.

3)3) Increase in VAT normally < 0.04 sec. VAT is the Increase in VAT normally < 0.04 sec. VAT is the time taken for the impulse to traverse the thickness time taken for the impulse to traverse the thickness of LV wall and therefore increases in LVH.of LV wall and therefore increases in LVH.

4)4) Counterclockwise rotation of heart so that the Counterclockwise rotation of heart so that the transition zone is shifted to right i.e. in lead V3 or transition zone is shifted to right i.e. in lead V3 or V2.V2.

LVH and StrainLVH and Strain Deep S wave in V1 – V2, tall R wave in V4 – V6Deep S wave in V1 – V2, tall R wave in V4 – V6 R wave in AVL 18mm.R wave in AVL 18mm. R in lead I + S in lead III is 39mm.R in lead I + S in lead III is 39mm. QRS axis is at 0.QRS axis is at 0. T wave inversion in V3 – V6.T wave inversion in V3 – V6. LAE: Delayed and wide terminal P wave in V1.LAE: Delayed and wide terminal P wave in V1.

Abnormalities of ST segment and T waveAbnormalities of ST segment and T wave

The T wave force or vector is usually directed away The T wave force or vector is usually directed away from the compromised region.from the compromised region.

In LVH, the hypertrophied LV is under strain and thus In LVH, the hypertrophied LV is under strain and thus T wave vector is directed away from left and towards T wave vector is directed away from left and towards right.right.

T wave will consequently be inverted in left oriented T wave will consequently be inverted in left oriented leads V5, V6, I, AVL and upright in V1, V2, AVR.leads V5, V6, I, AVL and upright in V1, V2, AVR.

TV1 taller than TV6 syndrome. This is an early TV1 taller than TV6 syndrome. This is an early expression of rightward T wave deviation in which T in expression of rightward T wave deviation in which T in V1 is taller than T in V6.V1 is taller than T in V6.

The abnormal T wave has blunt apex, asymmetrical The abnormal T wave has blunt apex, asymmetrical limb, the proximal limb is shallower than distal limb.limb, the proximal limb is shallower than distal limb.

Associated ST segment is minimally depressed with Associated ST segment is minimally depressed with slight upward convexity.slight upward convexity.

Left Atrial EnlargementLeft Atrial Enlargement LAE evidence constitutes a corroborative evidence LAE evidence constitutes a corroborative evidence

to the presence of LVH.to the presence of LVH. This is particularly useful pointer to the potential This is particularly useful pointer to the potential

LVH in the presence of LBBB. LVH in the presence of LBBB.

DIFFERENTIATION BETWEEN LBBB & LVHDIFFERENTIATION BETWEEN LBBB & LVH One general rule for differentiating between One general rule for differentiating between

LBBB & LVH is that the greater the amplitude LBBB & LVH is that the greater the amplitude of QRS complex the more likely is LVH ,the of QRS complex the more likely is LVH ,the more prolong the duration of QRS complex more prolong the duration of QRS complex the more likely is LBBBthe more likely is LBBB

Klein and colleagues have suggested that in Klein and colleagues have suggested that in the presence of LBBB either of the following the presence of LBBB either of the following criteria are associated with LVHcriteria are associated with LVH

> S wave in V2 + R wave in V6 >45mm.> S wave in V2 + R wave in V6 >45mm. > Evidence of LAE with QRS complex>0.16s > Evidence of LAE with QRS complex>0.16s

Frontal Plane QRS axisFrontal Plane QRS axis

Early stages of LV systolic overload are usually Early stages of LV systolic overload are usually associated with normally directed QRS axis.associated with normally directed QRS axis.

The mean vector is increased in magnitude but The mean vector is increased in magnitude but shows little change in direction.shows little change in direction.

Long standing LVH, QRS axis begins to deviate to Long standing LVH, QRS axis begins to deviate to left due to the development of associated fibrosis left due to the development of associated fibrosis which affects anteriosuperior division of left bundle which affects anteriosuperior division of left bundle branch and reflects the beginning of LAHB. branch and reflects the beginning of LAHB.

The QRS axis is commonly directed in the region The QRS axis is commonly directed in the region of 0.of 0.

CAUSES OF LEFT AXIS DEVIATIONCAUSES OF LEFT AXIS DEVIATION

1.1. LAHBLAHB

2.2. Inferior wall MI.Inferior wall MI.

3.3. Some presentation of WPW syndromeSome presentation of WPW syndrome

4.4. Pacing from apex of left or right ventrical.Pacing from apex of left or right ventrical.

5.5. Congenital heart diseases.Congenital heart diseases.

> Endocardial cushion defects> Endocardial cushion defects

> Tricuspid atresia.> Tricuspid atresia.

> Hypoplastic RV.> Hypoplastic RV.

> single ventrical.> single ventrical.

> CTGV. > CTGV.

Frontal Plane T wave axisFrontal Plane T wave axis

The T wave axis is directed to right as the T wave The T wave axis is directed to right as the T wave vector is deviated away from the compromised vector is deviated away from the compromised region.region.

T wave axis is deviated away from the QRS axis T wave axis is deviated away from the QRS axis resulting in progressive widening of QRS – T angle resulting in progressive widening of QRS – T angle which is normally 45which is normally 450 0 ..

Due to this there is progressive lowering of T wave Due to this there is progressive lowering of T wave in lead I and tall T wave in lead III.in lead I and tall T wave in lead III.

This reflects empirically small equiphasic QRS This reflects empirically small equiphasic QRS complex with flat T wave in AVF. complex with flat T wave in AVF.

Differentiation between LVH and LAHBDifferentiation between LVH and LAHB

Duration of QRS: In LAHB there is slight increase Duration of QRS: In LAHB there is slight increase in QRS duration but not beyond 0.11 sec. Criteria in QRS duration but not beyond 0.11 sec. Criteria for QRS duration not greater than 0.11 sec is for QRS duration not greater than 0.11 sec is necessary for diagnosis of uncomplicated LAHB.necessary for diagnosis of uncomplicated LAHB.

Left QRS axis deviation in LAHB is deviated Left QRS axis deviation in LAHB is deviated superiorly and to left and the mean QRS axis may superiorly and to left and the mean QRS axis may be located within the range of -30be located within the range of -3000 to -80 to -800 0 and and reflects empirically deep S in II, III, AVF and tall R reflects empirically deep S in II, III, AVF and tall R in AVL.in AVL.

The normal small initial Q wave in I and AVL The normal small initial Q wave in I and AVL becomes accentuated.becomes accentuated.

Slurring or irregularities of R wave in lead AVR and Slurring or irregularities of R wave in lead AVR and lead I and of S wave in lead V5, V6.lead I and of S wave in lead V5, V6.

Increase in magnitude of QRS deflection, tall R in I, AVL and Increase in magnitude of QRS deflection, tall R in I, AVL and deep S wave in II, III.deep S wave in II, III.

This increase in magnitude will not be reflected in This increase in magnitude will not be reflected in V5, V6. There is attenuation of R wave in V5, V6 V5, V6. There is attenuation of R wave in V5, V6 due to superiorly directed dominant QRS vector due to superiorly directed dominant QRS vector which tends to be directed away from the left which tends to be directed away from the left precordial leads.precordial leads.

Development of prominent S wave in V5, V6 in Development of prominent S wave in V5, V6 in LAHB also an expression of superiorly directed LAHB also an expression of superiorly directed dominant QRS forces.dominant QRS forces.

Left anterior hemiblockLeft anterior hemiblock QRS axisQRS axis more left than -30 degrees more left than -30 degrees initial R wave in the inferior leads (II, III and aVF)initial R wave in the inferior leads (II, III and aVF) Small Q waves inleads I and AVLSmall Q waves inleads I and AVL Usually normal QRS durationUsually normal QRS duration Increased QRS voltage in limb leads Increased QRS voltage in limb leads absence of any other cause of absence of any other cause of left axis deviationleft axis deviation Left ventricular hypertrophy Left ventricular hypertrophy In the presence of left anterior hemiblock the In the presence of left anterior hemiblock the

diagnostic criteria of LVHdiagnostic criteria of LVH are changed. Rosenbaum are changed. Rosenbaum suggested that an S wave in lead III deeper than 15 mm as suggested that an S wave in lead III deeper than 15 mm as predictive of LVH. predictive of LVH.

Left atrial hypertrophy Left atrial hypertrophy M shaped P wave in lead II M shaped P wave in lead II P wave duration > 0.11 seconds P wave duration > 0.11 seconds terminal negative component to the P wave in lead V1terminal negative component to the P wave in lead V1

Summary of LVHSummary of LVH Scoring system for LVH:Scoring system for LVH:

Other criteriaOther criteria Sokolow + Lyon Sokolow + Lyon (Am Heart J, 1949;37:161)(Am Heart J, 1949;37:161)

S V1+ R V5 or V6 > 35 mm S V1+ R V5 or V6 > 35 mm

Framingham criteria Framingham criteria (Circulation,1990; (Circulation,1990; 81:815-820)81:815-820) R avl > 11mm, R V4-6 > 25mm R avl > 11mm, R V4-6 > 25mm S V1-3 > 25 mm S V1-3 > 25 mm R V5 or V6 > 35 mm, R I + S III > 25 mmR V5 or V6 > 35 mm, R I + S III > 25 mm

Diagnostic CriteriaDiagnostic Criteria for low voltagefor low voltage Voltage of entire QRS complex in all limb leads Voltage of entire QRS complex in all limb leads <<5mm. 5mm. Voltage of entire QRS complex in all precordial leads Voltage of entire QRS complex in all precordial leads << 10mm. 10mm. Either criteria may be met to qualify as "low voltage". Either criteria may be met to qualify as "low voltage".

Differential DiagnosisDifferential Diagnosis An increase in the distance between the heart and the An increase in the distance between the heart and the ECG leads, infiltration of the heart muscle itself and metabolic ECG leads, infiltration of the heart muscle itself and metabolic abnormalities are all associated with low voltage. abnormalities are all associated with low voltage.

Increased Distance Increased Distance Pericardial effusion Pericardial effusion Obesity Obesity COPD with hyperinflation COPD with hyperinflation Pleural effusion Pleural effusion Constrictive pericarditis Constrictive pericarditis

Infiltrative Heart Disease Infiltrative Heart Disease Amyloidosis Amyloidosis Scleroderma Scleroderma Hemachromatosis Hemachromatosis

Metabolic Abnormality Metabolic Abnormality Myxoedema Myxoedema

Electrocardiographic findings in restrictive Electrocardiographic findings in restrictive cardiomyopathy cardiomyopathy

Example 1Example 1: (Limb-lead Voltage Criteria; e.g., R in : (Limb-lead Voltage Criteria; e.g., R in aVL >11 mm; note wide QRS/T angle) aVL >11 mm; note wide QRS/T angle)

Example 2Example 2: (ESTES Criteria: 3 points for voltage in : (ESTES Criteria: 3 points for voltage in V5, 3 points for ST-T changes) V5, 3 points for ST-T changes)

ECG Criteria of LV Diastolic Overload/ECG Criteria of LV Diastolic Overload/Volume OverloadVolume Overload

Tall R wave in left oriented leads V5, V6.Tall R wave in left oriented leads V5, V6. R waves are very tall, sometimes 40 to 50 mm R waves are very tall, sometimes 40 to 50 mm

specially in cases of AR, MR.specially in cases of AR, MR. MR does not usually manifest with deep S wave in MR does not usually manifest with deep S wave in

right precardial leads.right precardial leads. The tall R waves are due to displacement of heart The tall R waves are due to displacement of heart

forward and closer to the chest by a giant LA as forward and closer to the chest by a giant LA as occurs with MR.occurs with MR.

The R wave in lead V6 is of less magnitude in PDA The R wave in lead V6 is of less magnitude in PDA and least in VSD.and least in VSD.

The S wave magnitude in V1 is least in MR and The S wave magnitude in V1 is least in MR and largest in AR, PDA.largest in AR, PDA.

Deep and narrow Q waves in left oriented leads V5, Deep and narrow Q waves in left oriented leads V5, V6 from 2 to 4 mm in depth sometimes 5 to 10 mm V6 from 2 to 4 mm in depth sometimes 5 to 10 mm depth in VSD reflects hypertrophy of basal part of depth in VSD reflects hypertrophy of basal part of IVS.IVS.

The tall T waves in left precardial leads V5, V6 The tall T waves in left precardial leads V5, V6 symmetrical sharply pointed or arrow head in symmetrical sharply pointed or arrow head in appearance.appearance.

Tall T and tall R in V5, V6 suggests LV diastolic Tall T and tall R in V5, V6 suggests LV diastolic overload.overload.

ST segment in V5, V6 minimally elevated and ST segment in V5, V6 minimally elevated and concavity upwards.concavity upwards.

Severe MRSevere MR LAE: - Wide and notched P wave in I, III, AVL,V4-V6LAE: - Wide and notched P wave in I, III, AVL,V4-V6

- P terminal force is 4 X 0.08 = 0.32mm sec.- P terminal force is 4 X 0.08 = 0.32mm sec. LV Diastolic overload: Tall R in V5 – V6LV Diastolic overload: Tall R in V5 – V6

- Tall symmetrical T wave in V5 – V6- Tall symmetrical T wave in V5 – V6

- S wave in V1 is relatively small in amplitude due to the - S wave in V1 is relatively small in amplitude due to the anterior displacement of LV by enlarged LA. anterior displacement of LV by enlarged LA.

QRS axis is directed to about +80 indicating the beginning of QRS axis is directed to about +80 indicating the beginning of rightward deviation and possible development of PH.rightward deviation and possible development of PH.

Mitral Regurgitation with pulmonary hypertensionMitral Regurgitation with pulmonary hypertension Biatrial enlargementBiatrial enlargement: Wide and notched P wave in all : Wide and notched P wave in all

frontal plane leads and V4 – V6. P terminal force is frontal plane leads and V4 – V6. P terminal force is 1.5 X 0.04 = 0.06mm sec1.5 X 0.04 = 0.06mm sec

Relatively large amplitude of initial P wave deflection Relatively large amplitude of initial P wave deflection in frontal plane (RAE).in frontal plane (RAE).

LV Diastolic overload: Tall R in V6 with upright and LV Diastolic overload: Tall R in V6 with upright and symmetrical T wave, small amplitude of S wave in V1.symmetrical T wave, small amplitude of S wave in V1.

Biventricular Enlargement

The enlargement or hypertrophy of both ventricles The enlargement or hypertrophy of both ventricles produces complex ECG patterns.produces complex ECG patterns.

The effect of enlargement of one chamber may The effect of enlargement of one chamber may cancel the effect of enlargement of other.cancel the effect of enlargement of other.

1)1) ECG evidence of LVH with right axis deviation.ECG evidence of LVH with right axis deviation.

2)2) ECG evidence of LVH with clockwise rotation of ECG evidence of LVH with clockwise rotation of heart.heart.

3)3) ECG evidence of LVH with relatively tall R wave in ECG evidence of LVH with relatively tall R wave in V1 and R/S ratio > 1. V1 and R/S ratio > 1.

4)4) Eisenmenger syndrome usually manifests as: Eisenmenger syndrome usually manifests as:

a). Tall R wave in left precordial leads.a). Tall R wave in left precordial leads.

b). Tall R wave in right precordial leads.b). Tall R wave in right precordial leads.

c). Large equiphasic QRS complex in mid c). Large equiphasic QRS complex in mid epicardial leads. Kartz-wachtel epicardial leads. Kartz-wachtel

phenomena. phenomena.

5)5) When P wave is reflecting left atrial abnormality When P wave is reflecting left atrial abnormality manifest in the combination with any one of the manifest in the combination with any one of the following:following:

a). R/S ratio in lead V5, V6 equal to or < 1.a). R/S ratio in lead V5, V6 equal to or < 1.

b). S wave in V5, V6 > 7 mm.b). S wave in V5, V6 > 7 mm.

c). Right QRS axis deviation. c). Right QRS axis deviation.

Classic feature of VSD with PH – RVH with LV Diastolic Classic feature of VSD with PH – RVH with LV Diastolic overloadoverload

RVH: Tall R wave and inverted T wave in V1 – V3.RVH: Tall R wave and inverted T wave in V1 – V3. LV Diastolic overload: Tall R wave, tall upright T wave and LV Diastolic overload: Tall R wave, tall upright T wave and

deep narrow q wave in V5 – V6.deep narrow q wave in V5 – V6.