ECG Flashcards
how can you tell the P wave is from the SA node?
its the one that looks normal
how can you tell that conduction was initiated at the AV node?
will be negative deflections where there should be positive
narrow QRS complex?
indicates junctional rhythm
rhythm initiated at AV node
negative deflected P wave?
initiated at the AV node
-going in the opposite direction of normal
what if all P wave have different morphology?
if all positive - from atrium
what if P wave is absent or upside down and irregular?
junctional escape complex
how do you know if the P wave is too large?
height less than 2.5mm lead II
width less than 0.12s lead II
often biphasic lead V1
what is the significance of large P waves?
atrial hypertophy
what is the PR interval?
AV nodal delay
what is a clinically important aspect of PR interval?
need atria to empty before beating
average length of PR interval?
up to 0.2s
what is the QRS?
ventricular depolarization
must it always have a Q wave to be a QRS complex?
no
what is the significance of a Q wave?
depolarization left to right across IV septum
first negative deflection (if there is one)
are Q waves abnormal?
no
why is QRS more narrow than P wave?
faster conduction in the ventricles
blood is sent in complete opposite direction
what is the ST segment
ventricular ejection
should be flat and baseline
significance of ST segment?
ischemia - depression
infarction - elevation
what is a T wave
ventricular repolarization
normal appearance - like P wave, but bigger
will deflect same direction as P wave
what is the QT interval
all of the ventricular activity
tachycardia
rapid heart rate
bradycardia
slow heart rate
junctional tachycardia
junctional rhythm above 100 bpm
bc its AV nodal driven
how do you describe part of heart initiating conduction if it is not sinus or junctional node?
supraventricular vs. ventricular
saw tooth p waves?
atrial flutter
PAC
premature atrial conduction
-aka APCs
PVC
premature ventricular conduction
-widened QRS complex
what is ventricular fibrillation?
see a really weird pattern
physiologic lead?
lead II
what is rotation?
orientation of vectors along transverse plane
R wave progression
should get more positive from V1 to V6
right ventricular hypertrophy?
tall R waves V1-2
left ventriclar hypertrophy?
tall S waves in V1 and tall wave in V5 (often V4-6)
