ECG etc. Flashcards
P wave is upright in:
I, II, aVF, V4-6
What is the PR interval? And how long is it?
The time from the SA node to reach the ventricle muscle fibers.
0.12-0.2 s.
QRS length
0.05-0.10 s.
Q wave is upright in:
How tall is it?
I, aVL, aVF, V5-6.
1-2 mm.
ST elevation and depression:
No more than 2 mm in chest or 1 mm in standard.
No more than 0.5 mm.
ST elevation can be indicative of:
Injury or ischemia.
ST depression can be indicative of:
Subendocardial injury.
T wave is inverted in:
Elelvation:
I, II, aVF, V3-6.
No more than 5 mm in standard and no more than 10 mm in chest.
QT duration is:
What can changes in the QT be indicative of?
Length of ventricular systol.
Can be indicative of myocardial ischemia, injury or infarction.
Inverted T waves can mean:
Ischemia.
Changes in the Q wave can mean:
Necrosis or infarction.
P-mitrale
Broad, notched P waves that are taller in lead I than III.
P-pulmonale
Flat P wave in I with a tall and pointed P wave in leads II, and III.
AV Junctional rhythm
Inverted P waves in leads II and III with short PR interval.
Prolonged PR interval can be from (2):
AV block
Hyperthyroidism.
Shortened PR interval can be from (5):
Junctional rhythms Wolff-Parkinson-White syndrome Lown-Ganong-Levine syndrome Glycogen storage disease HTN
What are the best leads for reading P waves? (2)
Lead I and V1
Each dark line is how long?
Each light line is how long?
- 2 s
0. 04 s.
What can cause a P wave to follow a QRS complex? (2)
SVT
Junctional rhythm
No P waves can mean:
AFib, atrial flutter, junctional tachycardia
Lateral circumflex a. can be noted in which leads?
I, aVL, V5, V6
RCA can be noted in which leads?
II, II, aVF.
Septal/LAD can be noted in which leads?
V1, V2
Anterior/LAD can be noted in which leads?
V3, V4
PAC
Normal and seen in absence of heart disease. Can be aggravated by stress, caffiene, alcohol, etc.
See drawing.
PVC
Can also be normal or in patients with a history of heart problems (CHF, electrolyte problems, AMI).
P wave is absent before a QRS complex that is long and wide.
See drawing.
MAT - multifocal atrial tachycardia
3 different P waves caused by different atrial foci causing a depolarization.
Rate is tachycardic.
Supraventricular tachycardia (SVT)
P and T waves are indistinguishable from QRS. Can be in alteration.
Vtach
Big, wide QRS complex in rapid succession w/ no identifiable P waves. Rate is tachy.
VFib
Peaks/waves are not distinguishable.
Caused by multiple ventricular foci firing without synchronicity.
STEMI vs NSTEMI
STEMI s complete blockage of a vessel.
NSTEMI is partial blockage.
NSTEMI (3)
ST segment depression.
T wave inversion.
Elevated cardiac enzymes.
NSTE ACS (3)
ST segment depression.
T wave inversion.
Normal cardiac enzymes.
If thinking an MI, what do the T wave, ST elevation and Q wave tell you?
Inverted T wave suggests ischemia.
ST elevation suggests injury.
Q wave suggests necrosis/infarction.
Zones of infarction (3)
Infarction (dead tissue - cannot depolarize): Q wave
Injury (poor blood supply - unable to fully depolarize): ST segment
Ischemia (poor blood supply - cannot repolarize): T wave
What would you expect to see if the MI damage is old?
Return to baseline of the ST segment.
When thinking of a posterior wall STEMI, what should you observe?
Reciprocal changes form the anterior wall leads (V1-3)
Cardiac biomarker for MI and timeline of its elevation
Troponin I 1-4 hrs post event it is detectable. Peaks at 10-24 hrs. Persists for 5-14 days. Renal failure can cause a false positive.
Lab values for someone w/ AMI (3)
High WBC count
High CRP
High BNP due to ventricular wall stress due to increased fluid.
