DR. RAGHOBA

• DR. RAGHOBA T. GAONKAR

• JUNIOR PHYSICIAN

• NORTH DISTRICT HOSPITAL – GOA

SCOPE OF ECG DR. RAGHOBA

1. ECG LEADS

2. NORMAL ECG

3. TACHY ARRYTHMIAS

4. BRADY ARRYTHMIAS

5. ISCHAEMIC HEART DISEASE

6. BUNDLE BRANCH BLOCK

7. ECTOPICS

8. CHAMBER ENLARGEMENT

9. POTASSIUM DISTURBANCES

10.MISCELLANIOUS

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ORIENTATION OF THE 12 LEAD ECG

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AXIS OF ECG

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COMPONENTS OF NORMAL ECG COMPLEX DR. RAGHOBA

NORMAL ECG VALUES

P waves : P amplitude < 2.5 mm and width < 2.5 mm. May see notched. Best seen in lead II

PR Interval: 0.12 - 0.20 sec i.e. max one big square

q-waves :are narrow (<0.04s duration) and small (<25% the amplitude of the R wave). They are

often seen in leads I and aVL when the QRS axis is to the left of +60°, and in leads II, III, aVF when

the QRS axis is to the right of +60°.

Septal q waves should not be confused with the pathologic Q waves of myocardial infarction.

QRS Duration: 0.06 - 0.10 sec i.e. around max three small squares

QT Interval (QTc ≤ 0.40 sec)

Bazett's Formula: QTc = (QT)/Sq Root RR (in seconds)

ST segment: is a misnomer, because a discrete ST segment distinct from the T wave is usually

absent. More often the ST-T wave is a smooth, continuous waveform beginning with the J-point

(end of QRS), slowly rising to the peak of the T and followed by a rapid descent to the isoelectric

baseline or the onset of the U wave. This gives rise to an asymmetrical T wave. In some normal

individuals, particularly women, the T wave is symmetrical and a distinct, horizontal ST segment

is present.

Normal ST segment elevation: this occurs in leads with large S waves (e.g., V1-3), with concavity

upwards; this is often called early repolarization

T wave :The normal T wave is usually in the same direction as the QRS except in the right precordial leads. In the normal ECG the T wave is always upright in leads I, II, V3-6, and always inverted in lead aVR.

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QRS axis : The normal QRS axis range (+90° to -30° ); this implies that the QRS be mostly

positive (upright) in leads II and I

Precordial leads:

• Small r-waves begin in V1 or V2 and progress in size to V5.

• In reverse, the s-waves begin in V6 or V5 and progress in size to V2.

• Small "septal" q-waves may be seen in leads V5 and V6.

U Wave : amplitude is usually < 1/3 T wave amplitude in same lead. Direction is the same as T wave direction in that lead

Rate : 60 – 100 per min i.e. 3 -5 big squares

Correlate with old ECGs

Amplitude of complexes will be affected by thickness of chest wall

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NORMAL

Sinus rhythm PR interval max 0ne square

R-R interval between 3-5 squares

QRS max 3 small squares

ST segment normal t waves upright except aVR Normal axis

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SINUS TACHYCARDIA

Sinus rhythm R-R interval < 3 squares

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SVT

Regular Narrow QRS complex Tachycardia No definite P waves

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ATRIAL FIBRILLATION

Irregular Narrow QRS complex Tachycardia Irregular R-R interval

Baseline wavy No definite P waves

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ATRIAL FLUTTER

Narrow QRS complex Tachycardia Irregular or regular R-R interval

Baseline saw toothed No definite P waves

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MULTIFOCAL ATRIAL TACHYCARDIA (MAT)

Narrow QRS complex Tachycardia Irregular or regular R-R interval multifocal P' waves at least 3 different P wave morphologies in a given lead

Varying PR interval Commonly seen in COPD

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VENTRICULAR TACHYCARDIA

Regular broad QRS complex Tachycardia No P & QRS relation

Capture & fusion beats may be seen

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VENTRICULAR FIBRILLATION

Irregular broad QRS complex Tachycardia Chaotic rhythm

No definite P or QRS

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TACHYCARDIA

NARROW/NORMAL QRS BROAD QRS

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NARROW/NORMAL QRS TACHYCARDIA

DEFINITE P WAVES

REGULAR

PRESENT

ABSENT

SINUS TACHYCARDIA

SVT

MAT/PAT

DEFINITE P WAVES

IRREGULAR

PRESENT

ABSENT

BASELINE

IRREGULAR

SAW TOOTHED

ATRIAL FLUTTER

ATRIAL FIBRILLATION

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BROAD QRS TACHYCARDIA

EACH QRS PRECEEDED BY P WAVE

NO P &QRS RELATION

SINUS RHYTHM WITH BROAD QRS

ALMOST REGULAR R-R

INTERVAL

IRREGULAR R-R

INTERVAL / CHAOTIC RYTHM

VENTRICULAR TACHYCARDIA

VENTRICULAR FIBRILLATION

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SINUS BRADYCARDIA

Sinus rhythm R-R distance > 5 squares

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FIRST DEGREE HEART BLOCK

Sinus rhythm P-R interval > one square

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2 nd DEGREE A-V BLOCK

Sinus rhythm Some P waves not followed by QRS complex

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COMPLETE HEART BLOCK

bradycardia

No association between p and qrs i.e. pr interval is varying

Constant pp and rr interval

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NODAL RHYTHM

Bradycardia No P waves

Regular narrow QRS

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SICK SINUS SYNDROME

Sinus pauses i.e. Missed p waves Seen in elderly

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BRADYCARDIA

P WAVES ABSENT P WAVES SEEN

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P WAVES SEEN

MISSED QRS

PRESENT

ABSENT

P & QRS RELATION

ABSENT CONSTANT

COMPLETE HEART BLOCK

SINUS BRADYCARDIA

A V BLOCK

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ABSENT P WAVES

SICK SINUS SYNDROME

NO SINUS PAUSES

INTERMITTENT SINUS PAUSE

NODAL RYTHM

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ANTERIOR WALL MI

ST elevation in V1 - V6 Reciprocal ST depression in inferior leads

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EVOVLED ANTERIOR WALL MI

T waves inverted

Q waves developed

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INFERIOR & LATERAL WALL MI

ST elevation in II, III and Avf, V5 V6 Reciprocal ST depression in anterior leads

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POSTERIOR WALL MI

ST depression in V1 V2

May have ST elevations in V5 V6 i.e. lateral leads

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UNSTABLE ANGINA

Horizontal ST Depression Anginal symptoms

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RIGHT BUNDLE BRANCH BLOCK

Broad QRS M pattern in right sided leads i.e. V1 V2 Reciprocal T inversion usually present in

right sided leads

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LEFT BUNDLE BRANCH BLOCK

Broad QRS M pattern in left sided leads i.e. V5 V6

Reciprocal T inversion usually present in left sided leads

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ECTOPICS

VPC APC

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VPC

Early onset broad QRS No preceding P wave

Usually associated with T inversion Complete compensatory pause

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APC

Early onset narrow QRS Deformed P wave

Incomplete compensatory pause No reciprocal T wave inversion

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VENTRICULAR BIGEMINY

Alternating normal QRS and ventricular ectopic

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LEFT VENTRICULAR HYPERTROPHY WITH STRAIN

LVH – S wave in V1 + R wave in V5 or 6 > 35 mm i.e. 7 squares R + S in any leads > 45 mm Downsloping ST depression in lateral leads V5,V6,I,AvL

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ATRIAL ENLARGEMENT

P wave height > 2.5 small square P wave width >2.5 small square

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P PULMONALE DR. RAGHOBA

RIGHT VENTRICULAR HYPERTROPHY

R/S ratio < 1 May be associated with p pulmonale, RBBB Right axis deviation i.e. deep s in lead I

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HYPOKALAEMIA

usual triad of: ST depression, low T waves or inversion, and large U waves

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HYPERKALAEMIA

Tall peaked broad based t waves Suspect in kidney failure patients

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WRONG LEAD PLACEMENT

Positive QRS in aVR Deep S wave and small R in lead I

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EARLY REPOLARISATION DR. RAGHOBA

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COMMON NONSIGNIFICANT ABNORMALITIES

1. T inversion in V1-3 in females

2. Isolated T inversion or q wave in lead III

3. Minor conduction defects in limb leads

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