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43 Cards in this Set

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ECG nml axis describe lead I & aVF
Both +
LAD describe leads I & aVF
I = + aVF (-)
RAD describe I & aVF
I (neg) aVF (+)
Extreme axis describe I & aVF
both negative
LAD is associated with what disorder?
Left anterior hemiblock seen in CAD
RAD is seen when?
often nml finding in children and young adults
Left posterior hemiblock
RVH, pulm HTN
How do you determine HR on an ECG
1500/# of little squares
300/# of big squares
What is the nml P-R interval? What does a long PR inerval mean? What does a short P-R mean?
3-5 small squares should be no longer than 1 big square.
1 degree block
short could be WPW
What are the causes of a widened QRS?
BBB, PVC, TCA toxicity, WPW
What is the nml duration of a QRS?
1/2 big square
<100 ms
What is the nml QT interval? How do you correct for time?
QTc = 340-430 ms
QTc= QT/sq rt(RR in sec)
Rule of thumb QT should be 40% of RR
What do the squares on the ECG mean in terms of time?
Big square = 0.2 sec or 200 ms
small square = 40 ms
What arrthymia develops from a prolonged QT inerval?
Torsades de pointes
What are the more common causes of prolonged QT interval?
TCA overdose
Hypo Ca, Mg, K
quinidine, procanamide, amiodarone, starvation, CNS injury, liquid protein diet
What can non-sedating antihistamines do to an ECG?
Prolong the QT interval exacerbated by erthromycin, ketakonozole, hepatic dysfunction.
35 yo Female with allergies resently prescribed Hismanal who was noted to have an abnml ECG. What was the cause? She has an infection what should you not prescribe?
QT prolongation exacerbated by erthromycin
What shortens the QT
hypercalcemia and digitalis
Describe the nml p wave
< 2 mm high
< 120 mm (3 sm squares wide)
+ in lead II and - aVR also look in V1
Describe the p wave in right atrial enlargement? Left atrial enlargement
RAE = peaked p
LAE = widened p wave neg V1
Peaked T waves are associated with what?
Hyperacute MI
intracerebral hemorrahge
V1 V2 evloving post MI
think about symetry of t wave
Focal flipped T waves?

Unknown question
Prominent U waves indicate what
Increased tendency to Toorsades de pointes, hypokalemia, bradycardia, digitalis, amiodarone
Diffuse flipped T waves?
diffuse ischemia
metabolic abnml
Intracerebral hemmorhage
What is the sig of negative U waves
U waves in a different direction from T wave always significant casues are ischemia, HTN Aortic valve dz, RVH
What are the 3 main causes of ST elevation?
Acute MI
Prinzmetal angina
Pericarditis or myocarditis
Describe 4 rules to determine axis on an ECG?
1. I & aVF both + = nml
2. I(+) aVF(-) = LAD
3. I(-) aVF(-) = extreme axis
4. I(-) aVF(+) = RAD
In what leads are ischemic changes seen in a septal MI?
In what leads are ischemic changes seen in a anteroseptal MI?
In what leads are ischemic changes seen in a anerior MI?
In what leads are ischemic changes seen in a lateral MI?
I aVL V6
In what leads are ischemic changes seen in a posterior MI?
Tall R waves in V1-V2
In what leads are ischemic changes seen in a inferior MI?
What does ST depression indicate?
1. subendocarial ischemia
2. V1-V2 = posterior MI
3. Dig tox
4. LVH
5. Hypokalemia
6. LV strain (ST depression with flipped T Waves)
What are the criteria for LVH?
Flipped T waves in V1-V2
S in V1 + R in V5 35 mm
R peak time > 50ms watch out for WPW!
May also have strain pattern ST depression + flipped T waves
Describe the specificity and sensitivity of voltage criteria for LVH & RVH
Specificty is fairly good (low FP) Sensitivity is horrible (lots of FN)
What are the ECG criteria for RVH
ST depression + fipped T wave V1
Large R wave V1
Criteria for LBBB
QRS 120-180ms 3-4.5 sqs
RR' V6 SS' V1
T wave flipped
Criteria for RBBB
QRS >120 ms 3sqs
RSR' in V1
When interpreting an ECG, right ventricular hypertrophy (RVH) can mimic which of the following conditions?

B. AV block
C. True posterior MI
The prominent anterior forces seen in RVH are also seen in a number of other conditions including a true posterior MI. Thus, RVH is sometimes referred to as a pseudoinfarct.
RBBB and WPW could also result in prominent anterior forces but they may be distinguished in other ways. (rSR' morphology in V1, delta waves, and short PR.)
What are the ECG criteria for RVH?
Right axis deviation ( I negative AVF +)
R wave > S wave in V1 & S wave > R wave in V6
What are the ECG criteria for LVH?
R in V5,6 + S in V1,2 >35
R in AVL >13 mm
Repolarization abnml
List the 7 potential causes of arrhythimas?
HIS DEBS (Acronym)
Ischemia & Irritability
Sympathetic stimulation
Electrolyte disturbances
Stretch such as in CHF LAE
What are the 4 most important questions in determining the origin of an arrhythmia?
1. Are nml P waves present?
2. QRS duration < 0.12 sec?
3. Relationship between P & QRS?
4. Regular or Irregular?