Dr Samira Arami General Cardiologist

Conductive system

LEAD TYPEPOSITIVE INPUTNEGATIVE INPUT Standard Limb Leads Lead ILeft armRight arm Lead IILeft legRight arm Lead IIILeft legLeft arm Augmented Limb Leads aVRRight armLeft arm plus left leg aVLLeft armRight arm plus left leg aVFLeft legLeft arm plus right arm

Precordial Leads* V1V1 Right sternal margin, fourth intercostal space Wilson central terminal V2V2 Left sternal margin, fourth intercostal space Wilson central terminal V3V3 Midway between V 2 and V 4 Wilson central terminal V4V4 Left midclavicular line, 5th intercostal space Wilson central terminal V5V5 Left anterior axillary line [†] Wilson central terminal V6V6 Left midaxillary line [†] Wilson central terminal V7V7 Posterior axillary line [†] Wilson central terminal V8V8 Posterior scapular line [†] Wilson central terminal V9V9 Left border of spine [†] Wilson central terminal

ECG Leads Limb leads: I, II, III, aVR, aVL, aVF, Chest leads: V1-V6  Anterior surface: V1-4.  Inferior surface: II, III and aVF.  Lateral surface: I, aVL and V5-6.

ECG Paper

ECG Complex

WAVE OR INTERVAL DURATION (msec) P wave duration<120 PR interval (3-5mm) QRS duration< (2.5-3mm) QT interval (corrected) ≤ *

ECG Interpretation  Rhythm  Rate  Axis  P, QRS,Intervals  ST & T changes  Other abnormalities

Normal Sinus Rythm  Positive P in I,II  HR=  Regular RR intervals  PR>120msec

 Heart Rates= 300/RR interval(large squares) or 1500/RR interval(small squares)  Bazzet`s formula : QTc = QT/ √RR(sec)

Axis (mean QRS axis): normally -30 to +90 LAD: LVH LAFB Inf. MI RAD: Normal RVH Lat. MI LPFB

Normal ECG

P-wave Normal values 1. Polarity. up in all leads except aVR. 2. Duration. < 2.5 mm. 3. Amplitude. < 2.5 mm. Abnormalities 1. Inverted P-wave  Junctional rhythm. 2. Wide P-wave (P- mitrale)  LAE 3. Peaked P-wave (P-pulmonale)  RAE 4. Saw-tooth appearance  Atrial flutter 5. Absent P wave  Atrial fibrillation

QRS complex Normal values  Duration: < 2.5 mm.  Morphology: progression from Short R and deep S (rS) in V1 to tall R and short S in V6 with small Q in V5-6 (qRs). Abnormalities : 1. Wide QRS complex  Bundle branch block.  Ventricular rhythm. 2. Tall R in V1  RVH.  RBBB.  Posterior MI.  WPW syndrome. 3. abnormal Q wave [ > 25% of R wave]  MI.  Hypertrophic cardiomyopathy.  Normal variant.

ST- segment Normally it's isoelectric. [i.e. at same level of RP segment] Abnormalities: 1. ST elevation:  Acute MI.  Prinzmetal angina.  Acute pericarditis.  Early repolarization. 2. ST depression:  Ischemia.  Ventricular strain.  BBB.  Hypokalemia.  Digoxin effect.

T-wave Normal values. 1. Polarity:  Always up in I,II,V4-5  Always down in aVR.  Variable in III, aVL, aVF, V amplitude: < 10mm in the chest leads. Abnormalities: 1. Peaked T-wave:  Hyper-acute MI.  Hyperkalemia.  Normal variant. 2. T- inversion:  Ischemia.  Myocardial infarction.  Myocarditis  Ventricular strain  BBB.  Hypokalemia.  Digoxin effect.

QT- interval Definition: Time interval between beginning of QRS complex to the end of T wave. Normally: At normal HR: QT ≤ 11mm (0.44 sec) (or ) QTc = QT/ √RR Abnormalities: 1. Prolonged QT interval: hypocalcemia and congenital long QT syndrome. 2. Short QT interval: hypercalcemia.

Mitral P Pulmonar P

Criteria of ventricular enlargement LVH : 1. SV1 + (RV5 or RV6) ≥ 35 mm (or) RV5 or RV6 ≥ 25 mm 2. LV strain 3. LAE RVH : 1. Relatively tall R in V1 2. RV strain 3. RAD

LVH

RVH with RAE

Bundle system and sites of block

Complete Left Bundle Branch Block QRS duration ≥ 120 msec Broad, notched, or slurred R waves in leads I, aVL, V 5 and V 6 Small or absent initial r waves in right precordial leads (V 1 and V 2 ) followed by deep S waves Absent septal q waves in leads I, V 5, and V 6 Prolonged time to peak R wave (>60 msec) in V 5 and V 6

Complete Right Bundle Branch Block QRS duration ≥ 120 msec rsr ′, rsR ′,, or rSR ′, patterns in leads V 1 and V 2 S waves in leads I and V 6 ≥ 40 msec wide Normal time to peak R wave in leads V 5 and V 6 but >50 msec in V 1

Left Bundle branch block (LBBB)

Right Bundle branch block (RBBB)

Incomplete RBBB

Left anterior fascicular block (LAFB)

Bifascicular block (RBBB+LAFB)

Trifascicular block 1

ST segment and T wave changes in ischemia and MI

Lateral ischemia

Inferolateral ischemia

SVT with ischemia

NSTEMI

Evolution of ECG changes in MI

Hyperacute MI

Acute anteroseptal MI (STEMI)

Acute anterolateral MI (with hyperacute T)

Acute anterolateral MI

Acute inferoposterior MI

Right ventricular infarction

SAH

Hyperkalemia

Sever hyperkalemia

Atrial ectopic

Atrial bigeminy

Junctional ectopic

Ventricular ectopic with compensatory pause

Ventricular ectopic without compensatory pause

V. bigeminy

V. trigeminy

R on T event

R on T phenomena

Multifocal V. ectopics

V. Couplet

Tachycardia  Wide or Narrow  Regularity  P wave  P and QRS Rate and Association  Axis  Abnormalities

Sinus tachycardia

Sinus arrhythmia

Paroxysmal supraventricular tachycardia [PSVT]

SVT

SVT with retrograde P- wave

Atrial fibrillation [fine]

Atrial fibrillation [coarse]

AF + LBBB

Atrial flutter

Multifocal atrial tachycardia

Accelerated junctional rhythm

SUPPORTS SVTSUPPORTS VT Slowing or termination by vagal toneFusion beats Onset with premature P waveCapture beats RP interval ≤100 msecAV dissociation P and QRS rate and rhythm linked to suggest that ventricular activation depends on atrial discharge, e.g., 2 : 1 AV block rSR ′ V 1 P and QRS rate and rhythm linked to suggest that atrial activation depends on ventricular discharge, e.g., 2 : 1 VA block Long-short cycle sequence “Compensatory” pause Left-axis deviation; QRS duration >140 msec Specific QRS contours (see text) Major Features in the Differential Diagnosis of Wide QRS Beats Versus Tachycardia

Non-sustained VT

Ventricular tachycardia (VT)

VT

VT (with RBBB pattern)

VT (with LBBB pattern)

VT with capture beat

VT with fusion beat

Twisting VT (Torsades de pointes)

Ventricular fibrillation

Sinus bradycardia

Sinus arrhythmia

Junctional rhythm

Sinus arrest

Sino-atrial exit block

SA exit block

Sick sinus syndrome

First degree heart block

Second degree heart block Mobitz type I (Wenckebach block)

Second degree heart block Mobitz type II

Complete heart block

High degree AV block

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