Studied by 0 people
Looks like no one added any tags here yet for you.
Information we get from 12-lead ECG (what is incorrect)
anatomical orientation of heart in the body
relative thinness of the heart muscle and size of ventricles
previous damage to the heart
Acute MI
relative thickness and chamber size
Correct what doesn’t belong
Information we get from rhythm strip
Presence of arrthymias
Irregular/premature beats
presence of any blocks not arrythmias
exercise increases heart rate → o2 demand by heart →
ischemia (if CAD is present) → ST-segment depression
impulse originates at the
SA node @ R. atrium starting wave of depolarization
Spreads across left and…
r. atria (atria depolarize & contract)
wave of depolarization goes into
AV Junction , pauses for 0.13 s to wait for atrial contraciton/ventricular filling to complete
Goes down the l. r. ____
bundle branches
carries stimulus → ventricles heart apex then outward to…
after bundle branches →
Purkinje fibers on both sides then→
After Purkinje Fibers →
left and right ventricles
-depolarize, contract
after ventricles depolarize, they…
repolarize, relax, cycle restarts
An uwpward deflection/wave is
positive
A downward deflection/wave
negative
A deflection/wave that rests on the baseline
isoelectric
A deflection/wave that is partially negative is and positive is
biphasic
Sinus node impulse precedes ____ but not visible on ECG
P wave
P wave
represents atrial depolarization (contraction)
small deflection b4 QRS complex
P-R interval
measured from start of P wave to beginning of QRS
Time it takes for stimulus → atria → pass thru AV junction
QRS COMPLEX REPRESENTS…
ventricular depolarization (contraction)
QRS width represents
time req for a stimulus → spread thru ventricles
Does every QRS have a Q wave, R, and an S wave
no
First deflection of QRS = negative
Q-wave
First positive deflection in QRS is
R wave
A negative defleciton following R wave is
an S wave
Atrial depolarization occurs but is hidden
in QRS complex
ST measurement
from end of Qrs to start of T wave
ST segment marks
depolarization beginning
A normal ST segment is
isoelectric
J point
junction between QRS complex and beginning of the ST segment
T wave
Represents ventricular depolarization
QT interval
measure from the beginning of the Q wave to the end of the T wave
QT interval reps…
ventricular refractory period (time to depolarize then depolarize)
U wave
small deflection after T wave
final phase of ventricular repolarization
_______ detect voltages of the cardiac currents donated to these locations
electrodes
Each lead is measuring the same event (one cardiac cycle)
at the same time but lead view it from a different angle
Lead I
La -RA
Lead 2
LL - RA
Lead III
LL - LA
Basic laws of ECG correct
A positive deflection will not appear if any lead if the wave repolarization spreads toward → positive pole of lead
A negative deflection appears if any lead if wave of depolarization spreads toward → negative of that lead
A biphasic deflection will appear if depolarization spread to left angles to any lead axis
a positive deflection will appear if (Depolarization)
r. angle
______ or voltage of ECG waves is measured vertically
Amplitude
(duration) is recorded horizontally
Width
ECG chart paper moves at….
Each mm of ECG paper is = ______
25mm/s
0.04 s
<60bpm
>100bpm
bradycardia
tachycardia
PAC
impulse originates in atria, but not from SA node
normal P-waves (or not visible)
normal QRS width
PVC
impulse originate @ ventricles
no P-wave, wide, aberrant QRS >0.12s
T-wave and QRS point app directions
3+ ___’s = ventricular tachycardia
Unifocal PVCs
originate from same ectopic focus in ventricles
PVC’s that look the same
Multifocal PVC’s
originate from more than one ectopic focus in ventricles
PVC’s that look different
