EKG quiz 2

What are the limb / bipolar leads?

I- pos electrode on L shoulder, neg electrode on R shoulder

II- pos electrode on L foot, neg electrode on R shoulder

III- pos electrode on L foot, neg electrode on L shoulder

what are augmented leads?

one physical lead on pt, one theoretical neg pole in center of heart (Wilsons terminal)

aVL, aVR, aVF

Where is aVL placed?

pos lead on L shoulder, looking at central terminal

where is aVR placed?

pos lead on R shoulder and looking at central terminal

where is aVF placed?

pos lead on L foot and looking up at terminal central

What are the hexaxial leads?

first 6 leads of 12 lead

I, II, III, aVR, aVL, aVF

What does the hexaxial reference system determine?

normal axis of heart

what are precordial / chest leads?

unipolar leads which use central terminal as neg pole

V1-V6

where is V1 placed?

4th ICS R of sternum

where is V2 placed?

4th ICS L of sternum

where is V3 placed?

directly bt V2 and V4

where is V4 placed?

5th ICS at midclavicular line

where is V5 placed?

level w/ V4 at left anterior axillary line

where is V6 placed?

level w/ V5 at midaxillary line (directly under armpit)

what leads look at septal wall?

V1 and V2

what leads look at anterior wall of LV?

V3 anda V4

what leads look at lateral wall of LV?

I, aVL, V5, V6

what leads look at inferior wall?

II, III, aVF

what are contiguous leads?

2 or more leads which look at same area of heart

-V1-V4

-II, III, aVF

-I, aVL, V5, V6

what leads are used to determine cardiac axis?

I and aVF

What would a normal axis look like on ECG?

both I and aVF mostly positively deflected

what would an ECG w/ LAD show?

I mostly pos. aVF mostly neg

What does RAD look like on ECG?

I mostly neg, aVF mostly pos

How does extreme RAD show on ECG?

both I and aVF mostly neg deflected

what is often very first sign of cardiac ischemia?

hyperacute T waves

what are hyper acute T waves?

broad, inc in amplitudes and symmetrical

what represents subendocardial ischemia?

ST seg depression

what represents transmural ischemia / injury?

ST seg elevation

What do pathological Q waves represent?

infarction and actual death of cardiac tissue, either from previous or acute cardiac event

What is criteria for pathological Q waves?

longer than 0.04 s in duration (1 small box)

deeper than 2 mm or 2 small boxes

or deeper than 25% of height of R wave if present

what is this

pathological Q waves

what are reciprocal changes?

mirror image of cardiac event on opposite leads which look at same area of heart

confirmatory sign of cardiac ischemia

list the reciprocal leads

septal: V1, V2 and none

anterior: V3, V4, and none

anteroseptal: V1-V4 and none

lateral: I, aVL, V5, V6 and II, III, aVF

anterolateral: I, aVL, V3-V6, and II, III, aVF

inferior: II, III, aVF and I, aVL

posterior: none and V1-V4

what is a STEMI?

1 mm or more of ST seg elevation in 2 or more contiguous leads w/ or w/o reciprocal changes

what is this?

lateral wall STEMI (elevation in lateral leads I and aVL, reciprocal depression in inferior leads III and aVF)

what is this?

antero-septal STEMI (elevation in anterior and septal leads V1-V3)

what is posterior STEMI?

isolated ST depression in V1-V4 w/ no ST elevation anywhere

typically result of occlusion/stenosis of Lcx; must obtain posterior EKG

how do you obtain posterior EKG?

V4-V6 moved to back of pt and labeled V7-V9; also referred to as 15 lead

st elevation in these confirms posterior wall STEMI

how do you r/o RV involvement in inferior STEMI?

V4 moved to R of sternum 5th ICS midclavicular line; marked as V4R

elevation confirms RV involvement

what is MC intraventricular conduction abnormality during acute MI?

LAFB

what is LAFB criteria?

LAD- pos I and neg aVF

Q wave in I and R wave in III- q1r3

mostly neg II

mostly neg III

what is LPFB criteria?

RAD- neg I and pos aVF

R wave in I and Q wave in III- r1q3

mostly pos III

LBBB criteria

QRS complex longer then 0.12 s in duration (3 small boxes)- best measured in V1

RS pattern in V1- find J, travel backwards, first deflection is negative

double QRS- notching of QRS in lateral leads (I, aVL, V5, V6) best seen in V6

lack of Q waves in lateral leads

what is this?

LBBB- no Q in lat leads, notching of QRS, QRS wider than 0.12 s in V1, RS pattern in V1

RBBB criteria

QRS longer 0.12 s / 3 small boxes in V1

rSR pattern in V1- pos deflection behind J point

double QRs- slurred S waves in lateral leads (I, aVL, V5, V6) best seen in V6

what is this?

RBBB- slurred S in lat leads, rSR pattern and QRS wider than 0.12 s in VI

what is RAE also known as?

P-pulmonale

what is criteria for RAE?

upright P wave taller than 2.5 mm in limb leads

biphasic P wave w/ lager pos initial deflection and neg smaller terminal deflection in V1

what is LAE also known as?

P-mitrale

What is criteria for LAE?

upright humped P wave at least 0.12 s in duration and 0.4 s distance bt humps

biphasic P wave w/ small initial pos deflection and large neg terminal deflection in V1

RHV criteria

R:S ratio 1mm or more in V1-V2 (more R than S)

supportive:

• RAE

• RAD

• strain pattern- concave ST set turning into inverted asymmetrical T wave in V1-V2

exclusionary: RBBB, posterior wall MI, children < 8

what is this?

RVH

LVH criteria

causes LAD w/ deep S waves in V1-V2 and tall R in lat leads

• add deep S to taller R = equal to or greater than 35 mm

• R wave in aVL greater than 12mm

• any chest leads greater than 45 mm

what is this?

LVH

what are examples of STEMI mimics?

LVH, pericarditis, BER, brugada syndrome, LBBB, vent paced rhythm, hypothermia

what is MC STEMI mimic?

LVH (concave upward contour ST seg elevation in V1-V3, T wave inversion on lateral leads)

What are pericarditis ECG findings?

PR seg depression

global concave ST seg elevation

w/ no reciprocal ST depression anywhere (except aVR and V1)

PR seg elevation in aVR

what is early depolarization (BER)?

normal variant ST segment elevation; mostly in young men

-global concave shaped ST seg elevation

-terminal QRS notching (J wave fishhook sign or Osborn wave)

-large T waves (sometimes symetrical)

-no reciprocal ST seg depression on ECG anywhere outside of aVR and V1

how do you differentiate b/t pericarditis and BER?

w/ lead V6

BER- more T wave than ST elevation;

pericarditis- more ST elevation than T wave

what is brugada syndrome?

inherited arrhythmogenic dz which affects sodium channels of RVOT

MC in young males o Southeast asian decent

what are the two main findings of brugada syndrome?

type 1- Coved shape: convex shaped ST elevation in V1-V3

type 2- carousel horses sign: saddle shape type ST elevation in V1-V3

what is this?

brugada syndrome type 1

what is this?

brugada syndrome type 2

what is this?

pericarditis

what is this?

BER

hypothermia ECG findings

35C- sinus bradycardia followed by prolongation of intervals; below 32C- Osborn waves commonly mistaken for STEMIs

(changes in ECG due to acidosis not temperature)

how do you dx acute MI in presence of LBBB or vent paced rhythm?

sgarbossa’s criteria

what is sgarbossa’s criteria?

concordant ST elevation of 1mm or more in any lead w/ pos QRS

concordant ST depression of 1mm or more in V1-V3

discordant ST elevation of 5mm or more in any lead w/ neg QRS

what does this ECG show?

sgarbossa’s criteria

what is the WPW diagnostic triad?

short PR interval

wide QRS

delta wave

what is type A WPW?

left sided Kent bundle produces QRS complex that is mostly positive in V1

what is type B WPW?

Right sided Kent bundle produces QRS complex that is mostly neg in V1

what is a delta wave?

slurring upstroke of QRS, diagnostic of WPW

what is orthodromic AVRT?

anterograde conduction (towards vents) occurs through normal pathway and up accessory pathway

produces regular narrow complex tachycardia

what is antidromic AVRT?

conduction occurs down accessory pathway and up normal pathway, retrograde (towards atria)

produces regular, monomorphic and wide tachycardia