ECG Flashcards
how to calculate heart rate on an ECG
300/(number of large squares in an R-R interval)
what does sinus rhythm indicate
there is a p wave before each QRS complex
what does broad complex tachycardia with no p wave indicate
ventricular fibrillation or ventricular tachycardia
what does narrow complex tachycardia with abnormal or no p waves indicate
supraventricular tachycardia
how to determine axid deviation
Left axis deviation: R waves in Leads I and Leads II are LEAVING EACHOTHER (pointing away)
Right axis deviation: R waves in Leads I and Leads II are REACHING EACHOTHER (pointing towards)
what is the length of normal PR interval
3-5 small squares
when is PR interaval decreased
accessory conduction pathway
when is PR interval increased
heartblock/AV block
what is a narrow QRS complex
<0.12 secs. occurs when the impulse is conducted down the bundle of His and the Purkinje fibre to the ventricles (normal)
what is a broad QRS complex
> 0.12 secs. ccurs if there is an abnormal depolarisation sequence
how to tell if there is right bundle branch block
broad QRS complex
M shaped QRS in V1
W shaped QRS in V6
MaRRoW
how to tell if there is left bundle branch block
broad QRS complex
W shaped QRS in V1
M shaped QRS in V6
WiLLiaM
what does a tall R wave in V5 or V6 indicate
left ventricular hypertrophy but can be normal in physically fit people so look for other signs (t wave inversion in lateral leads)
what does a dominant R wave in V1 indicate
right ventricular hypertrophy if there are other signs too (right axis deviation, t wave inversion in v1-v3)
what do pathological Q waves indicate
> 25% the size of the R wave that follows it. indicates previous MI
