ECG Interpretation

Lecture 31

How does an electrocardiogram work?

ion movement in cell creates electric currents and movement of these current through cardiac tissue stimulates muscle contraction —> ECG is graphical representation of this electrical activity

What ion is extracellular?

Na+

What ion is intracellular?

K+

What wave is indicated by the blue star?

P

What wave is indicated by the blue star?

Q

What wave is indicated by the blue star?

R

What wave is indicated by the blue star?

S

What wave is indicated by the blue star?

T

What does the P wave stand for?

atrial contraction

What does the QRS complex stand for?

ventricular contraction

What does the T wave stand for?

repolarization

How do you place ECG leads on a patient?

White —> right forelimb

Black —> left forelimb

Red —> left hindlimb

Green —> right hindlimb

“White is right, smoke over fire”

What questions should you ask when reading an ECG?

Does this rhythm has a pulse associated with it?

Is it fast or slow (rate)?

Is it regular or irregular?

Are teh QRS compelxes wide or narrow/normal?

Is there a P wave for every QRS wave?

Is there a QRS wave for every P wave?

ASK IN THE SAME ORDER, EVERY TIME

What does “regularly irregular” mean?

it’s not right, but it is a predictable pattern

Example: sinus arrythmia

What does “irregularly irregular” mean?

random pattern, not right, not predictable

Examples: atrial fibrillation, VPCs, AV blocks

Normal QRS complexes are most likely of what origin?

supraventricular

Wide and bizarre QRS complexes are most likely of what origin?

ventricular

If you can consistently identify a P wave, the rhythm starts with what?

sinus

If there is not a QRS complex for every P wave, what rhythms can it be?

2nd degree AV block

3rd degree AV block

atrial flutter

If there is a QRS complex for every P wave and it is consistently and reasonably related, waht rhythms can it be?

sinus rhythm

sinus arrhythmia

sinus bradycardia

supraventricular tachycardia

APCs

If there is a QRS complex for every P wave and it is not consistently and reasonably related, waht rhythms can it be?

3rd degree AV block

ventricular tachycardia

If there is not a P wave for every QRS complex, what rhythms can it be?

atrial fibrillation

atrial standstill

ventricular tachycardia

VPCs

supraventricular tachycardia

APCs

escape complexes

What lead is the best one to pick up electrical activity in the heart?

lead II

What rhythms are associated with bradycardia?

sinus bradycardia

escape rhythms

AV block

SA block/arrest

atrial standstill

What rhythms are associated with a normal heart rate?

normal sinus

sinus arrythmia

atrial fibrillation

AV block

ventricular premature complexes (VPCs)

atrial premature complexes (APCs)

What rhythms are associated with tachycardia?

sinus tachycardia

atrial fibrillation/flutter

atrial tachycardia

ventricular tachycardia

ventricular premature complexes (VPCs)

atrial premature complexes (APCs)

What rhythm is shown?

2nd degree AV block

What rhythm is shown?

VPC

What rhythm is shown?

atrial fibrillation

What rhythm is shown?

ventricular tachycardia