Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Emergency Medicine > ECG > Flashcards

ECG Flashcards

You may prefer our related Brainscape-certified flashcards:
Royal College: Emergency Medicine flashcards
1
Q

What are the progressive ECG changes in a transmural MI?

A

Hyperacute (0-2h)- ST elevation, tall T waves, reciprocal changes

Fully evolved (24h)- Tomb stone appearance, T waves inverting, reciprocal changes

Resolution (24-48h)- Q waves becoming more prominent, ST beginning to fall, T waves inverted

Chronic (>48h)- Pathological Q waves ( broad >1mm and deep 3mm/ >1/3 QRS amplitude )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

For best outcomes, do PCI within?

A

90mins.

  • PCI should be done within 12h of onset.
  • May consider PCI in resolution phase if patient is young or still symptomatic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

STEMI + GTC = ?

A

VF.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the difference in pathology between a STEMI and NSTEMI?

A

STEMI- transmural MI; affects major coronary vessels and related to anatomical blood supply territories.
NSTEMI/UA- subendocardial infarction; affects small blood vessels and not related to anatomical blood supply territories

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How will an inferior, anterior and lateral STEMI present on ECG?

A
  • Sinus tachycardia

- Inferior MI: STE in II, III, aVF. Anterior MI: STE in V1,2,3. Lateral: STE in V5,6,I,aVL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is UA ddx from MI?

A

History, PE, serial ECGs, Trop T/I -ve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the ECG changes during treadmill test?

A
  • Normal at rest
  • ST depression on exertion
  • ddx UA from NSTEMI by reversion to normal at rest. NSTEMI DOES NOT revert to normal at rest.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

ST depression descriptions?

A

Reverse tick sign, horizontal ST, Horizontal downsloping ST

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the ECG changes in an inferior STEMI?

A
  • STE in II, III, aVF
  • reciprocal depression in V4-6, I, aVL
  • possible posterior STEMI shown by ST depression in V1-3 (place posterior leads to confirm)
  • check for RCA infarct by doing R sided ECG
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What else to look for in an inferior/post/RCA STEMI? Why?

A

Rhythm disturbances like conduction blocks.

This is because the SA and AV nodal artery arise from the RCA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the caveat for an RCA/inferior/posterior STEMI?

A

WITHOLD NITRATES! RV determines the preload of the LV. If preload falls, CO also falls, reducing CPP for the coronary arteries and exacerbating the ischemia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Mx of RCA/inferior/posterior STEMI?

A
  • MONA (including dual anti platelet)
  • if BP low–> Fluid Challenge 500ml in 0.5h to increase preload. Be conservative to prevent cardiogenic shock!
  • if BP still low–> transcutaneous pacing
  • if BP still low–> vasopressors e.g. dopamine infusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

isolated ST depression in V1-3?

A

Think NSTEMI or UA, since an isolated posterior infarct is rare. To confirm, do serial ECGs looking out for STE in inferior leads, cardiac enzymes.
** If patient very symptomatic and hypotensive, PCI may have a role. DO NOT BE TOO CAUTIOUS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the concept of coronary artery dominance?

A

The artery that supplies the Posterior Descending Artery (PDA) determines dominance-
Supplied by RCA (70%) = R dominant
Supplied by LCx (10%) = L dominant
Supplied by both (30%) = Co-dominant
This determines which artery supplies the AVN.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the blood supplies to SAN and AVN?

A

SAN- usually by RCA. Inferior STEMI can cause SAN to fail, producing an ectopic rhythm.
AVN- Usually by PDA. Dominance determines which artery supplies the AVN.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

STE in inferior, posterior and left lateral leads ?

A

Unlikely to be infarct of 2 different territories. This is likely a left dominant circulation.

17
Q

NSTEMI ECG changes?

A
  • ST depression and T wave inversions not specific to any anatomical blood supply territory
  • ECG normalizes after NSTEMI is over
18
Q

Mimics of MI

A

1) Grusin type II - concave upwards STE + tall T waves + prominent u waves BUT without reciprocal ST depression, all seen in precordial leads
2) Old MI - Evolved MI (24h) or resolving MI (24-48h) with STE, T wave inversion and Q waves; patient has missed the boat for PCI already
3) Ventricular Aneurysm - STE + pathological Q waves seen >2 weeks post-MI, most commonly in precordial leads.

4) Wellen’s syndrome - Asymptomatic patient with precordial leads showing Biphasic T waves (Wellen’s Type A) or Deeply and Symmetrically inverted T waves (Wellen’s Type B).
This sign is highly specific for critical stenosis of the LAD. Also, when a Wellen’s patient gets chest pain, pseudo normalisation of ST segments can occur. Even if symptoms mild, or cardiac enzymes normal –> CALL THE CARDIOLOGIST!!!

5) Pericarditis - Global STE w/o reciprocal changes + ST depression in aVR + PR interval shortening. When pericarditis resolves, ST segment normalizes and T waves become inverted.
6) Pulmonary embolism - classically sinus tachy + S1Q3T3 + T wave inversions + new RBBB (strain on R heart)

19
Q

4 types of conduction blocks?

A
  1. Sinus block
  2. AV (Heart) block - 1st degree, 2nd degree (Mobitz 1 & 2)
  3. BBB
  4. Hemiblocks
20
Q

What rhythm does a sinus block give rise to?

A

Escape rhythm - atrial, junctional

21
Q

In sick sinus syndrome, what is the tachycardia due to?

A

Escape rhythm

22
Q

What is the sequence of pacing in conduction blocks?

A

1) atropine
2) Transcutaneous pacing (look for pacing spikes)- temporary, painful and requires sedation
3) Transvenous pacing (by cardiology)
4) Permanent pacemaker, if all else fails

23
Q

Prolonged (>0.2s) but constant PR interval, P wave precedes QRS complex = ?

A

1st Degree Heart block

24
Q

Causes and Mx of 1st degree Heart block?

A

1) High vagal tone e.g. athlete
2) Beta blockers
3) Digoxin
4) CAD (ischemia)
5) Myocarditis

Not dangerous. Thus, treat underlying cause and not the rhythm.

25
Q

When suspect STEMI due to RCA occlusion, look for?

A

Conduction blocks!

26
Q

Progressive prolongation of PR interval followed by dropped beat, irregular bradycardia = ?

A

2nd Degree Heart block, Mobitz Type 1

27
Q

DDx 2nd degree heart block from compensatory pause or sinus arrest ?

A
  • no PAC/PJC/PVC preceding the pause

- has a p wave before the block

28
Q

Mx of Wenckebach phenomenon?

A

Treat underlying cause like ischemia, infarct, electrolyte disturbance

29
Q

Minimum number of p waves required to Dx mobitz type 1?

A
  1. 2 to show prolongation of PR, 1 to show the dropped beat
30
Q

Constant & normal PR interval + non-conducted P waves + bradycardia + p waves marching at constant rate

A

2nd degree Heart block, Mobitz type 2

  • these can have fixed ratio blocks or irregular
  • More serious because can have multiple p waves not being conducted to ventricles
31
Q

Tx of mobitz type 2?

A

1) Treat underlying cause

2) Treat the rhythm (due to possible hemodynamic compromise) in the same way as complete heart block.

32
Q

AV dissociation + PP interval constant + RR interval constant + Escape Rhythm (junctional or ventricular) ?

A

Complete (3rd degree) Heart block

33
Q

What kind of rhythm will the 3rd degree Heart block show?

A

Junctional or Ventricular Escape rhythm (40-60bpm and 20-40bpm respectively)

34
Q

Mx of Heart blocks?

A
  • Primary and Secondary survey
  • assess rhythm with 12-lead ECG
  • Hx and PE
  • Assess the type of heart block

If Mobitz Type 2 or CHB w/o serious SXS:
Send to CCU and observe. No need to commence pacing but make sure transcutaneous/venous pacing available. Treat underlying cause

If serious SXS :

1) Atropine 0.6mg, repeat - increases BP, does not solve block
2) Transcutaneous pacing (requires sedation and is a temporary measure to buy time) ; if unavailable, Dopamine OR Adrenaline
3) Transvenous pacing while trying to treat cause
4) Should step 3 fail, then put permanent pacemaker.

35
Q

When putting patient on pacing, what needs to be done?

A

Sedation with IV Midazolam 2-2.5mg and Morphine

36
Q

3 captures to look for to confirm successful pacing?

A

1) Electrical capture (every pacing spike followed by QRS)
2) Mechanical capture ( feel for pulse)
3) Clinical capture (BP rise)

37
Q

What does pacing look like?

A
  • Pacing spikes - atrial shows spike before p waves, ventricular shows spike before QRS.
  • Wide and Bizzare QRS complexes (resembling BBB or PVC)
38
Q

In a new LBBB or RBBB, suspect what?

A

new LBBB- suspect AMI (serial ECGs, trend, cardiac enzymes, correlate to SXS, scarbossa’s criteria)
new RBBB- suspect acute PE! (look for S1Q3T3, sinus tachy, Twave inversion and ST depressions, CXR, CTPA, D-dimer).

Emergency Medicine (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions