Electrocardiograms - Berger Flashcards
Leads: left (I), right (aVF)
Estimate the electrical axis. Is it normal?
Leads I and aVF equally positive. The axis will be midway between 0° and 90°.
~40-50 degrees
Normal
Leads: left (I), right (aVF)
Estimate the electrical axis. Is it normal?
Leads I and aVF both positive. Lead I more positive than aVF. The axis will therefore be oriented more toward 0°.
~20-40 degrees
normal
Leads: left (I), right (aVF)
Estimate the electrical axis. Is it normal?
Lead I positive. Lead aVF almost equiphasic. Therefore, the axis will be approaching 0°. (Note: when a lead is equiphasic, the axis will be 90° to that lead.)
~0 degrees
normal
Leads: left (I), right (aVF)
Estimate the electrical axis. Is it normal?
Lead I positive. Lead aVF negative.The axis will be oriented negatively past 0°.
~-30 degrees
left axis deviation
Leads: left (I), right (aVF)
Estimate the electrical axis. Is it normal?
Lead I negative. Lead aVF positive. The axis will be oriented positively past 90°.
~120 degrees
right axis deviation
Leads: left (I), right (aVF)
Estimate the electrical axis. Is it normal?
Both leads I and aVF negative. The axis will be oriented between -90° and -180°.
~-135 degrees
indeterminate
Estimate the heart rate
~79bpm
Describe some characteristics of a normal ECG
- every P followed by a QRS
- upright P in I, II, III
- PR interval between 0.12s and 0.2s
- HR 60-100bpm
What is the standard time scale on an ECG?
0.2s per major grid line (5mm), or 0.04s per minor grid line (1mm) -> overall 25mm/s
ST elevations and Q waves seen in which leads indicate an inferior wall problem?
II, III, aVF
ST elevations and Q waves seen in which leads indicate an lateral wall problem?
V5, V6, I, aVL
ST elevations and Q waves seen in which leads indicate an anterior wall problem?
V2, V4
How do you calculate corrected QT interval (QTc)?
measured QT / sqrt(RR interval)
Give the normal values for the following:
- PR
- QRS
- QTc
- PR: 0.12s to 0.2s
- QRS: < 0.1s
- QTc: < 0.44s
What range of mean QRS axis angles corresponds to:
- Normal?
- Left axis deviation?
- Right axis deviation?
- -30 to 90
- -30 to -180
- 90 to 180
Estimate the mean QRS axis
~-10
Describe the V1 and V6 findings in left ventricular hypertophy (LVH)
See image
Describe the V1 and V6 findings seen in right ventricular hypertophy (RVH)
See image
Identify
Left ventricular hypertophy (LVH)
(S in V1 > 24 mm, R in aVL > 13 mm) with strain pattern (ST segment depression and asymmetric T-wave inversions in leads I, aVL, V5, and V6 consistent with repolarization abnormality)
Identify
RVH
1) a tall R wave in V1 (as part of the qR complex), (2) right axis deviation, (3) T wave inversion in V1 through V3 , (4) delayed precordial transition zone (rS in V6 ), and (5) right atrial abnormality. An S1 Q3 pattern is also present and can occur with acute or chronic right ventricular overload syndromes.
Complete the table:
What type of MI shows a ST depression?
NSTEMI
What type of MI shows a ST elevation?
STEMI
Identify
Where is the lesion located?
STEMI (ST elevation)
Proximal LAD
Identify.
Where is the lesion located?
STEMI
Acute right ventricular infarction (inferior wall)
Identify
Subendocardial ischemia
Pathologic Q waves are evidence of what?
infarcted tissue (because necrotic tissue does not generate electrical forces)
Identify the condition associated with each T-wave abnormality shown here (A-F)
- A: normal
- B: subendocardial ischemia
- C: hyperkalemia
- D: hypercalcemia
- E: hypocalcemia
- F: subepicardial ischemia
Name the condition associated with each of the following ST-T changes (A-G)
- A: normal
- B: early repolarization
- C: epicardial injury
- D: subendocardial injury
- E: digitalis
- F: hypokalemia, quinidine, cerebral hemorrhage
- G: strain
