Irwan M. Loebis, dr., SpJP

ELECTROCARDIOGRAPHY

UNSWAGATI, CIREBONUNSWAGATI, CIREBON

Lecture outlinePart oneInformation provided by ECGCardiac conduction system: anatomy and

physiology (Normal) ECG interpretationPart two Abnormal ECG

ECG is…?Printout as a result of a particular

electrical function of the heart

The standard 12-lead electrocardiogram is a representation of the heart's electrical activity recorded from electrodes on the body surface

Information provided by Information provided by ECG: what do you think?ECG: what do you think?

Cardiac conduction system

SA nodeAV nodeBundle His

Impulse Transmission

SA Node Internodal branch AV Node Hiss Bundle Purkinje Fiber Contraction

the sequentialactivation (depolarization) of the right

and left atria

right and left ventricular depolarization (normally the ventricles are activated simultaneously)

ventricular repolarization

One ‘complex’ of ECG waveform

Leads positionLeads position

Limb leadsLimb leads

Einthoven Triangle

Chest lead

Chest leadChest lead

Chest leadChest lead

ECG interpretation…?1. Calibration2. Rate and rhythm3. QRS axis4. P morphology5. PR interval6. QRS duration7. QRS morphology8. ST segment morphology9. T morphology10. U morphology11. Others: LVH, LV strain, BBB, QT interval12. Conclusion: normal/abnormal

Calibration1 mV = 1 cmImportant in

assessing tall waves in hypertrophic state

Paper speed and normal value

One small box: 0.04 sOne small box: 0.04 sOne large box: 0.2 sOne large box: 0.2 sPR Interval: 0,12’’ - PR Interval: 0,12’’ - 0,20’’0,20’’QRS duration: 0,04’’ - QRS duration: 0,04’’ - 0,12’’0,12’’

Rate calculation Method:

300 divided by number of large boxes between R-R

1500 divided by number of small boxes between R-R,

Number of QRS complexes in 6 seconds times 10.

Rate calculationpaper 25 mm/s

Sinus Rhythm Sinus Rhythm

Rhythm: RegularRate: 60 – 100P wave: Normal in configuration; precede each QRSPR: Normal (0. 12 – 0.20 s)QRS: Normal (<0.12 s)

QRS Axis (N: - 30 s/d + 110)

P wave Wave of atrial depolarization Normal characteristic:1. Smooth and rounded2. ≤ 3 mm tall3. Upright in leads I, II avF

PR intervalIncluding P wave until the beginning of QRS

complexNormal duration is 0.12-0.2 seconds

QRS complex Wave of ventricular depolarization 5-20 mm tall Duration 0.06-0.10 seconds

QRS morphology qRs Rs R rS

QR Q/QS RsR’ rSr’

ST segmentBegins at J pointBetween ventricular depolarization and

ventricular repolarizationGenerally isoelectric

T wave Ventricular repolarization, followed by

ventricular relaxation Positive in lead : I, II, V3-V6 Negative in lead avR

Interpret this ECG..

And this..

Abnormal ECG Myocardial ischemia/infarct Hyperthrophy Hyperkalemia Arrhythmia

ACUTE CORONARY SYNDROMEACUTE CORONARY SYNDROME

No ST ElevationNo ST Elevation ST ElevationST Elevation

Unstable Angina

NSTEMI

Acute myocardial infarction

STEMI Non STEMI

Mid LAD occlusion after the first septal perforator (arrow) ECG : large anterior MI

Occlusion of diagonalbranch ( arrow )

ST elevation in I and aVL

ECG demonstrates large anterior infarction

Proximal large RCA occlusion

ST elevation in leads II, III, aVF, V5, and V6 with precordial ST depression

Small inferior distal RCA occlusion

ECG changes in leads II, III, and aVF

Acute inferoposterior MI

Questions…??

• Peaking T• Shortening QT interval

• Widening P wave, QRS complex• Prolongation PR interval

HIPERKALEMIA

PPM

How to identify arrhythmias ?

QRS complex Regular / irregular ?

QRS complexNormal-looking QRS complex?

Wide / narrow ?

P wave ?

Relationship between P and QRS ?

NORMAL SINUS RHYTHM

PSVT :-due to re-entry mechanism-narrow QRS complex-regular-retrograde atrial depolarization-P wave ?

PSVT

Atrial Fibrillation :

-from multiple area of re-entry within atria-or from multiple ectopic foci-irregular, narrow QRS complex-very rapid atrial electrical activity (400-700 x/min).-no uniform atrial depolarization

Atrial Flutter :

-The result of a re-entry circuit within the atria-Irregular / regular QRS rate-Narrow QRS complex-Rapid P waves (300x/min), “sawtooth”

Junctional rhythm:-AV junction can function as a pace maker (40-60 x/min).-due to the failure of sinus node to initiate time impulse or conduction problem.-normal-looking QRS.-retrograde P wave.-P wave may preceede, coincide with, or follow the QRS

VES

SR

SR SR SR SRSR SR

VES VES

Sinus rhythm with Multifocal VES

Sinus rhythm with VES couplet

Sinus Rhythm with VES, R on T

Ventricular Tachycardia

Torsade de Pointes

Ventricular Fibrillation

Prolonged PR interval

1st degree AV block

Missing QRS Missing QRS

2nd degree AV block, type 1

2nd degree AV block, type 2

Missing QRS

P P P P P P P

QRS QRS QRS

Total AV Block / 3rd degree AV block