EKG Basics Flashcards
Normal orientation for P waves in all leads
I - positive II - positive III - biphasic (negative ok) aVR - negative aVL - positive aVF - positive V1 - biphasic
In which leads are the P waves normally most positive and most negative?
most positive in II
most negative in aVR
Normal amplitude of a P wave
not exceeding 0.25mV (2.5 small squares)
Anterior leads
V2, V3, V4
Left Lateral Leads
I, aVL, V5, V6
Inferior leads
II, III, aVF
Right Ventricular leads
aVR, V1
What does the PR interval represent?
start of atrial depolarization to the start of ventricular depolarization
Length of normal PR interval
0.12 to ).20 sec (3 to 5 small squares)
What does the PR segment represent?
time from the end of atrial depolarization to the beginning of ventricular depolarization
See Q wave in which leads?
I, aVL, V5, V6, (ie left lateral leads) sometimes inferior leads and V3 and V4
What does a Q wave represent?
septal depolarization
Normal Q wave amplitude?
not greater than 0.1mV (1 small square)
In what leads are R waves (positive deflections) seen in the QRS complex?
I, II, III, aVL, aVF, V5, V6
In what leads are S waves (negative deflections) seen in the QRS complex?
aVR, V1