المحتوى غير شامل لكل ما تحتويه المحاضرات E.C.G References: - Doctor’s lecture - First Aid EM clerkship - ECG Intepretation made incredibly easy (5th edition) - Some YouTube videos - My notes المحتوى غير شامل لكل ما تحتويه المحاضرات

Amplitude= voltage Amplitude Time

1 small box = 0. 04 Sec = 0. 1 mV or 1 mm 1 big box= 0. 2 Sec= 0 1 small box = 0.04 Sec = 0.1 mV or 1 mm 1 big box= 0.2 Sec= 0.5 mV= 5 mm 5 big boxes = 1 Sec 2 large boxes= 1 mV

1) P wave= Atrial depolarization Amplitude: 2 to 3 small boxes Duration: less than 1 big box 2) PR interval= Atrial impulse from atria to AV node Duration: 3 small boxes to 1 big box ( 0.12 to 0.2 Sec) - Prolonged interval (>0.2 sec) may indicate heart block

3) QRS complex= ventricular depolarization Amplitude: 5 to 30 mm (remember 1 small box=1mm) Duration: 0.06 to 0.10 Sec A prolonged QRS complex may indicate Ventricular tachycardia and Bundle Branch Block (BBB) Left BBB - Right BBB 4) ST segment: usually isoelectric (flat) A change in the segment may indicate myocardial damage It may become elevated or depressed

Elevated ST segment 1) Acute MI 2) Pericarditis 3) Early repolarization pattern in the young

Depressed st segment 1) Unstable angina 2) Left ventricular strain pattern

5) T wave= ventricular repolarization Amplitude: 0.5 mm (remember 1 small box=1mm) Peaked/tented T wave indicate hyperkalemia, Subendocardial ischemia - Inverted T wave indicate LV Strain pattern Dynamic t-wave changes of ischemia 6) U wave: Not always show but when it’s there It may indicate hypocalcemia or hypokalemia

P waves before every QRS complex Sinus Rhythm P waves before every QRS complex Types of sinus rhythm: 1) Normal sinus rhythm (NRS) 2) Sinus tachycardia 3) Sinus bradycardia 4) Sinus arrhythmia

NSR

Sinus tachycardia

Sinus braycardia

Axis Normal Axis: ( -30 to +90) Right axis deviation: (+90 to 180) Left axis deviation: (-30 to -90)

Important POINTS A positive degree designation doesn't mean that the pole is positive – you have to check the leads- A wave pointing upward considered positive A wave pointing downward considered negative Infants and children normally have right axis deviation Pregnant women normally have left axis deviation

Axis significant Once you determine whether the axis is normal or deviated you can guess the cause For example the left axis deviation indicate these conditions: Wolff Parkinson white syndrome Inferior wall myocardial infarction Left ventricular hypertrophy So when you see left axis deviation on ECG you’ll think of these * This is just some of the causes not all of them

Quadrant method Observe the QRS complexes in lead ( l + aVF)

Observe the QRS complexes in lead ( l + aVF) Right axis deviation Observe the QRS complexes in lead ( l + aVF)

Left axis deviation Positive in lead l Negative in lead aVF and ll Observe the QRS complexes in lead ( l + aVF)

Now let’s start

1) dETERMINE THE RHYTHM Paper and pen method (Variation up to 0.04-one small box is normal)

2) Determine the rate 1) Regular= 300 / Number of big boxes between RR 2) Irregular= Number of QRS complex X 6  in 10 sec paper X 10  in 6 sec paper X 2  in 30 sec paper Remember: 5 big boxes= 1 sec Normal HR= 60 to 100 bpm

3) Evaluate p wave Is it present? Do all the waves have the same configuration? Do all have same size and shape? Is there p wave for every QRS complex?

4) Determine the duration of pr interval small square between the start of p wave and the start of QRS complex X 0.04 (since each small box=0.04) Now Is the duration in the normal range? 0.12 to 0.2? (3 to 5 small boxes) remember: 5 small boxes=1 big box Duration > 1 big box = 1st degree HB Duration < 3 small boxes= 1- Pre-excitation syndromes WPW Syndrome LGL Syndrome 2- Junctional rhythm

5) Determine the duration of QRS complex Is the duration in the normal range? 0.06 to 0.10 sec? Are all the complexes the same size and shape? Does a QRS complex appear after every p wave?

6) Evaluate t waves Are T waves present? Do they all have a normal shape? Do they all have a normal amplitude? Do they all have the same amplitude?

7) Determine the duration of the qt interval - Is the duration in the normal range? 0.36 to 0.4 Sec?

8) Evaluate any abnormality - Check ST segment for abnormalities - Check U wave presence

Abnormalities

Ventricular abnormalities Atrial abnormalities Atrial fibrillation Atrial flutter Supraventricular tachycardia Multifocal tachycardia Ventricular abnormalities Ventricular tachycardia Ventricular fibrillation

Atrial fibrillation Characteristic: No P wave Irregular Narrow complex Tachycardia Management: A) Stable: chemicals (beyond EMR level) B) Unstable: cardioversion

Atrial flutter Characteristic: Saw tooth Irregular Narrow complex * Narrow complex= less than 3 small boxes

Multifocal tachycardia Different shape of P wave Irregular

Supraventricular tachycardia Characteristic: No P wave Narrow complex Regular Management: A) Stable: 1- vagal+valsalva maneuver 2- adenosine – B blockers - Ca++ channel blockers B) Unstable: Cardioversion

Ventricular tachycardia Characteristic: Wide complex Regular Rapid Management: Pulse B) No pulse: defibrillation stable Unstable= cardiovesion

Torsade de points If unstable => cardioversion Refers to a ventricular tachycardia variation in which QRS axis swings from positive to a negative an a single lead Treatment: IV magnesium sulfate If unstable => cardioversion

Ventricular fibrillation Characteristic: Wide complex Irregular Bizarre Management: Defibrillation CPR

AV block More than 0.2 PR interval RR: regular or not PR: fixed or not

✔ ✗ Degree Regulation Consistency Treatment 1st degree شكرًا، مع السلامة 2nd degree Mobitz type l ✗ Mobitz type ll - Admission - pacemaker 3rd degree

1st degree

2nd MOBITZ type 1

2nd mobitz type 2

3rd

Anatomy of the conduction system Understand this before moving on

Understand this before moving on

Left bundle branch block (LBBB) The block occur before anterior and posterior fascicles split Ischemia can be masked with LBBB. (use of sgarbossa criteria can be helpful) ECG: QRS duration > 0.12 sec Large wide R waves in l, aVL, V5, V6 No Q waves in l, aVF, V5, V6 ST and T waves directed opposite to terminal 0.04-sec QRS

LBBB

Right bundle branch block (RBBB) In some circumstances when the right bundle is non functional as in RBBB The right ventricle must receive the signal for depolarization from left ventricle Sense this signal is not transmitted along the same specialized conductive tissues Depolarization of the right ventricle is slow compared to the left This results in wide QRS complex

RBBB * Ischemia in not masked with RBBB ECG: QRS duration > 0.12 sec Triphasic QRS complexes (rabbit ears) Regular sinus rhythm Wide S wave in l, aVL, V5, V6 *Triphasic= it means the trend of the ECG signal deflect. If there are thee deflection (i.e two positive and one negative) it's called triphasic

Biphasic QRS complex Triphasic QRS complex

RBBB

(اللهم انفعني بما علمتني وعلمني ما ينفعني وزدني علمًا) انتهى (اللهم انفعني بما علمتني وعلمني ما ينفعني وزدني علمًا) وفقنا الله جميعًا