EKG Flashcards
EKG paper?
small box:
time = 0.04sec
distance = 1.0mm
voltage(y-axis) = 0.1mV
Big box:
time = 0.20sec
distance = 5mm
voltage (y-axis) = 0.5mV
EKG
record of the electrical potentials generated during the cardiac cycle plotted against time
Unipolar leads?
aVR
aVL
aVF
Bipolar leads?
DI
DII
DIII
Precordial leads?
V1 —> V6
Anterior leads
V2, V3, V4
Left Lateral leads
I
aVL
V5
V6
Inferior leads
II, III, aVF
A quick estimate of the axis can be made by looking at which two leads?
I
aVF
Normal axis vs. the three types of deviations?
Normal axis = I(+) & aVF(+)
Left axis deviation = I(+) & aVF(-)
Right axis deviation = I(-) & aVF(+)
Extreme right axis deviation = (-) & aVF(-)
Where are the 6 Precordial leads placed?
V1: R. 4th space, R. of sternum V2: L. 4th space, L. to sternum V3: bw V2 & V4 V4: L. 5th space, Midclavicular line V5: L. 5th space, Ant. Axillary line V6: L. 5th space, Mid. Axillary line
Normal precordial leads show?
R-wave progressively gets larger
(-) Deflection
depolar. away from recorder
(+) Deflection
depolar. towards recorder
Biphasic deflection
- recorder placed in middle
1st) depolar toward recorder = (+) deflection
2nd) depolar away recorder = (-) deflectoin
*Order of ventricle depolar. vectors?
1st = septal vector 2nd = free wall LV 3rd = basal vector
Mean Electric Axis?
summation of ventricular depolar. vectors
Normal MEA?
Left Inf. Quadrant: 0-90 degrees
I (0)
II (60)
aVF(90)
Determine MEA with which leads in QRS?
I(+)
aVF(+)
*Sinus Tachycardia?
*Increased HR = HR>100beats/min
-due to Increased AP of SAN
normal P-wave, PR-I,
QRS = narrow
Rhythm = Regular
*Atrial fibrilation?
No P-wave Different beats (R-R)
*Ventricular fibrilation?
Random rhythm/completely chaotic
No HR
No clear p-waves, QRS, t-wave
Ventricular muscle: AP run into each other and cancel out
*First degree AV Block
*PR-I = (>0.20sec) = constantly prolonged the same duration
Wenchkebach (Mobitz I) AV Block?
HR = normal
p-wave: in Wenckebach (type I) their is dropped beats
p-waves that stand alone
*PR-I: progressively prolonged until a dropped beat
**the PR-I before dropped beat will be longer then the
one after
Rhythm: irregular
- ID = p-wave w/out QRS following
- prior p-wave = Most prolonged PR-I
- after p-wave = Least prolonged PR-I
Type II AV Block
HR = slow
*PR-I: constant w/ no changes
QRS: narrow (<0.12sec) and No R-wave after some p-waves
Rhythm: regular
**ID = p-wave w/ no QRS following
Prior PR-I: constant w/ no change
After PR-I: constant w/ no change
Third Degree AV Block
HR = slow (less than 100)
- p-wave: present & completely dissociated from QRS
- equal distance bw each p-wave
- one p-wave superimposed into QRS and alters S-wave
**ID: constant p-wave durations
one p-wave superimposed into QRS = altered S-wave
Techniques to measure or determine Right Ventricular Hypertrophy?
V1->V4 = decreased (amplitude) R-wave & progressively get
smaller
*V1 = R-wave(>7mm) >> S-wave V5,V6,V7 = S-wave > 7mm RAD = RA depolar.
Techniques used to measure or determine Left Ventricular Hypertrophy?
*2 (-)leads, 2(biphasic)leads, 2(+)leads
*V1(R-wave) + V5(R-wave) >> 35mm V5(R-wave) > 25mm aVF (R-wave) > 20mm aVL (R-wave) > 11mm DI(R-wave) + DIII(R-wave) > 25mm
*3-Features about Acute Myocardial Infraction?
Ischemia = ST-Seg. DEPRESSION Acute MI -> ST-Seg. = ELEVATION T-wave = INVERSION Anoxic injury = depolar. myocytes Necrosis-> Q-wave = DEEP
**Ischemia on EKG?
ST-Seg = DEPRESSION T-wave = INVERSION
*ischemia is reversible if BF is restored
*Acute MI on EKG?
ST-Seg = ELEVATION
Anoxic injury = depolar. by myocytes close to epicardium
*Necrosis on EKG?
Q-wave = DEEP
tiss. is electrically silent
*Hypokalemia on EKG?
ST-seg = Depression *T-wave = decreased Amplitude (flattened out) U-wave = increased H+
Cardiac arrhythmias
QRS = prolongation of time/duration P-wave = increased Amplitude & increased duration
*Hyperkalemia on EKG?
Increased [K+]e = 6-7mEq/L
-> earliest change: Peaking T-wave (High (A))
Greater Increase [K+] = 7-8mEq/L
-> Taller, Peaked (Greater (A)) T-wave w/ narrow
base
*Hypercalcemia on EKG?
*QT-In = DECREASED T-wave = normal ST-Seg = Decreased duration
Increased sensitivity to Digitalis
-may prevent arrhythemias
*Hypocalcemia on EKG?
*QT-In = Increased duration/Prolongation ST-Seg = Increased duration/Prolongation T-wave = normal
