Lecture 31: ECG Interpretation

ions to electricity

• ion movement in cells create electric currents

• movement of these currents through cardiac tissue stimulates muscle contraction

• muscle creates the pump that moves blood around the body

ECG =

graphical representation of electrical activity

normal sinus rhythm

• SA node

• AV node

• bundle of His

• bundle branches

• Purkinje fibers

what is the question you should ask when identifying a rhythm?

does this rhythm have a pulse associated with it?

what are the 5 questions you should ask for rhythm?

• is it fast or slow?

• is it regular or irregular?

• are the QRS complexes wide or narrow/normal?

• is there a P wave for every QRS wave?

• is there a QRS wave for every P wave?

regularly irregular rhythm

• pattern

• sinus arrythmia

irregularly irregular rhythm

• random

• atrial fibrillation

• VPCs

• atrioventricular blocks

identifying waves

• identify first the QRS complexes (bigger amplitude)

• identify the T waves after QRS complexes

• identify the P waves by exclusion of other waves

normal QRS complexes

mostly likely supraventricular origin

wide and bizarre QRS complexes

most likely ventricular origin

if you can consistently identify P waves, then the rhythm starts with

sinus (tachycardia, rhythm, or bradycardia)

if you can’t consistently identify P waves, then it can be

supraventricular tachycardia, atrial fibrillation, junctional tachycardia, atrial standstill, ventricular tachycardia

P waves vs QRS complexes

• check if every P wave has a subsequent QRS

• check if every QRS is preceeded by a P wave