Lec 31-32 ECG Flashcards
Which walls of heart does LADA supply? Which leads represent this?
anterior septum
anterior wall
antero-lateral wall of LV
V1-V6
Which walls of heart does circumflex artery supply? Which leads represent this?
high lateral and posterior wall of LV
I and aVL
Which walls of heart does right coronary artery supply? Which leads represent this?
SA node, inferior LV/ septum, RV
II, III, aVF
Which leads represent inferior wall?
leads II, III, aVF
== RCA
Which leads represent septal walll?
V1, V2
== LADA
Which leads represent anteroseptal wall?
leads V1 through V4
== LADA
Which leads represent lateral wall of LV?
leads I, aVL, V5, V6
I/aVL = circumflex = high lateral V5/V6 = LADA = anterolateral
Which leads represent RV?
right sided leads V4R to V6R
== RCA
Which leads represent posterior wall?
leads V7 to V9
leads V1 and V2 might reflect these
What is the first part of the heart to get ischemic in a partial occlusion?
subendocardium
What signifies ischemia [not infarction] on EKG?
ST depression or T wave inversion
How can you tell if ST is depressed?
compare ST segment to PR segment
if ST is at a lower voltage box than PR that means its depressed
What does ST elevation mean?
complete occlusion of epicardial artery = tells you acute injury occuring
What is the first change in EKG with infarction?
hyperacute T wave = tall T wave and within sec to min ST segment starts to rise
What is evolution of EKG changes in acute mI
- hyperacute T wave
- ST elevation
- t wave inversion
- Q wave formation
What does presence of pathological Q wave signify?
infarct = muscle death
If hours have passed since start of MI what will EKG show?
ST elevation and T wave reversed; maybe small Q starting to form
What happens to EKG in LBBB?
- broad QRS
- down V1
What is treatment if RV + inferior infarct vs just inferior infarct?
RV + inferior: if RV dying pt may become hypotensive b/c RV can’t pump blood to left side –> may go into cardiogenic shock; need to give fluids and avoid nitroglycerin [reduces preload]
basically: give fluids before you go to catch lab
if just inferior infarct –> don’t need to give fluids
What do ST depressions in V1 and V2 suggest?
alert us to the fact that posterior wall may be involved so we may need to put EKG leads on posterior wall
What is length of QRS in narrow complex vs broad complex tachycardia?
narrow: QRS < 0.12 sec [< 3 small sq]
broad: QRS > 0.12 sec [> 3 small sq]
What does narrow complex tachycardia mean vs broad?
narrow = its coming from supraventricular broad = its coming from ventricle
What kind of rhythm is atrial flutter?
- regular
- saw tooth P wave pattern
- seen best in II, III, aVF
- atrial rate ~300/min = 1 big box between
- classified as typical or atypical
What type of rhythm is atrial tachycardia?
- regular
- usually long PR interval
- atrial rate 150-200
- p wave morphology different than sinus
What type of rhythm is AVRT/AVNRT?
- regular
- short PR interval
- fast > 100/min
- narrow QRS
What type of rhythm is multifocal atrial tachycardia?
- irregularly irregular
- clear p waves but > 3 different P wave morphologies b/c different foci give rise to different P waves
What type of rhythm is atrial fibrillation?
- irregularly irregular ventricular rhythm
- absent P waves –> have fibrillary activity but no clear P waves
What type of rhythm is atrial flutter with variable block?
irregular
What types of rhythms should you think if narrow complex tachycardia with irregular rhythm?
- Afib
- atrial flutter with variable block
- multifocal atrial tachycardia
What type of rhythms should you think if narrow complex tachycardia with regular rhythm?
- sinus tach
- atrial flutter
- or any of the re-entrant tachycardias
Who most commonly gets multifocal atrial tachycardia?
acutely ill elderly patients especially with COPD
What kind of rhythm is sinus tachycardia?
- regular
- long PR interval
- upright in 1 and 2; inverted in aVR
- > 100/min
What is AVNRT/AVRT?
- re-entrant arhythmia
AVNRT = extra path for re-entry is within AV node hence dual AV nodal physiology
AVRT = accessory path not within AV node
What do you give to pt that has SVT?
give adenosine = blocks AV node so will block accessory path and shut it off; go back to sinus rhythm
How do you treat atrial flutter?
ablation and anti-arrhythmic
What is typical vs atypical atrial flutter?
typical = p waves upright in II, III, aVF
atypical is not
What distinguishes atrial flutter from AFib?
Atrial flutter = clear p waves actively going really fast
What causes atrial flutter?
macro re-entrant arrhythmia involving atria [either right or left]
What causes atrial tachycardia?
ectopic focus in atrium
can be enhanced by digitalis toxicity
What causes wide complex tachycardia?
- ventricular tachycardias [VT/VF/torsades]
What should you think with wide QRS tachycardia?
wide QRS tachycardia is VT until proven otherwise
What signs of ventricular tachycardia?
- wide QRS tachycardia
- evidence of AV dissociation –> independent P waves, capture or fusion beats
- history of ischemic heart disease or CHF
What kind of shock do you give pt with VTach?
synchronized cardioversion
When do you give synchronized cardioversion vs non-synchronized defibrillation?
synchronized cardioversion = if there are any QRS waves present
defibrillation = in VFib
What can happen if you give non-synchronized shock to pt with ventricular tachycardia?
- can set off extra burst of energy and become VFib
What is AV dissocation?
no association between rhythm of P waves and QRS waves = happens in ventricular tachycardia
What is capture beat?
p wave is able to capture a narrow normal QRS in the middle of VT pattern
happens in ventricular tachycardia
What is fusion beat?
have QRS in between supraventricular and ventricular beat = not as broad as ventricular or as narrow as supraventricular
happens in ventricular tachycardia
What is rhythm of ventricular fibrillation?
- chaotic and irregular deflections of varying amplitude and contour
- no p waves, QRS complexes, or T waves
What is torsade de pointes?
- associated with long QT interval [congenital or due to drugs, electrolyte imbalances]
- form of polymorphic VT
- dancing/twisting around an axis
How do you treat torsade de pointes?
don’t cardioverst or fibrillate
just give a huge bolus of Mg
How do you differentiate WPW from other causes of wide QRS?
VT/VF = regular rhythm WPW = wide QRS
How would you treat patient with WPW with AFib?
procainamide or pronesta
What do you use lidocaine for?
VT
What happens if you give adenosine to pt with WPW?
block AV node and everything will come down accessory path –> will become a VF
When is adenosine indicated/contraindicated?
indicated in narrow complex tachycardia
contraindicated in broad complex tachycardia
What kind of rhythm with a first degree AV block?
- PR interval > 0.2 sec [> 5 small boxes]
- each p wave followed by QRS
- usually constant PR interval
just a slowed down AV node
What happens in mobitz type 1 [wenkebach] second degree AV block?
progressive prolongation of PR until P wave fails to conduct
group/pattern beating
What happens in mobitz type 2 second degree AV block?
intermittent non-conducted P waves with no evidence of atrial prematurity
What kind of pattern is mobitz type 1 second degree AV block?
- irregularly irregular
- pr interval gradually prolongs
short –> longer –> longest –> dropped p wave –> subsequent PR interval after dropped P wave is the shortest
What kind of pattern is mobitz type 2 second degree AV block?
- irregularly irregular
- lots of extra p waves
- > 3 p waves for each QRS but no group beating like in wenkebach
- have fixed PR length
What happens in complete heart block?
- p waves not conducted to the ventricles because of blood at AV node
- p waves show no relation to QRS complexes
- ventricles depolarized by a ventricular escape rhythm
What is sinus pause?
longer than 2 seconds [10 big boxes] of NO sinus activity
What is sinus arrest/asystole?
no sinus activity
What do you normally see in pacemaker EKG?
- wide QRS
- usually LBBB pattern –> wide and down in V1
- pacemaker spikes before P, before QRS, or both
Why do you get LBBB pattern in pacemaker KEG?
you put pacemaker leads into R side of heart because you can’t get leads into L [atrial] side of heart.
depolarization via R ventricle first –> then L depolarized via intramyocardial conduction
What does you see in hyperkalemia EKG?
peaked T waves
long PR –> no P at high level
What is treatment for hyperkalemia?
Iv calcium gluconate for membrane stabilization
insulin + Bicarb to shift K into cells
What do you see in serum potassium < 5.5?
normal EKG
What do you see in serum K5.5-6.5?
- peaked T wave
- prolonged PR
What do you see in serum K 6.5-8?
- peak T
- loss of P
- prolonged QRS
- ST elevation
What do you see in serum K > 8?
- progressive widening of QRS = looks like sine wave
- ventricular fibrillation/asystole/axis deviation/ bundle branch block
What do you see on EKG in hypokalemia?
- prominent U waves [best in leads V2, V3] = major finding
- can have small/absent T waves
What do you see on EKG in acute pericarditis?
- diffuse concave upward ST elevation [w/ no reciprocal changes]
- PR depression in V3, PR elevation in aVR
- maybe tachycardia
What is electrical alternans?
- QRS axis/amplitude alternates between beats
- sign of cardiac tamponade
What do you see on EKG in cardiac tamponade?
- electrical alternans –> voltage changes in QRS between successive beats, axis changes [sometimes + or -]
- low voltage QRS due to so much fluid around the heart
What do you see on EKG in pulmonary embolism?
- sinus tachycardia
- S1Q3T3 pattern –> promiment S wave in lead 1 + Q wave and inverted T in lead III
What are 3 things that cause ST elevations
- acute MI [STEMI], unstable angina
- hyperkalemia
- acute pericarditis
What do you see on EKG with digoxin?
- scooped out ST depression = reverse check mark sign
- also will see AFib [since its treating AFib] –> no Ps and irregularly irregular
What does it mean for there to be sinus rhythm?
- upright in II, II, down in aVR
- p before every Q
What is normal variation in HR with respiration?
< 10%
What are some causes of sinus tachycardia?
- pain
- fever
- hypoxia
- pulm embolism
- hypovolemia
- sepsis
What are some causes of right axis deviation?
- right ventricular hypertrophy
- left posterior fascicular block
- lateral/apical MI
- acute right heart strain [due to acute lung disease like pulm embolus]
- chronic lung disease [COPD]
- dextrocardia
- WPW via LV free wall accessory path
- hyperkalemia
- secundum ASD
What is most common cause of right axis deviation?
right ventricular hypertrophy
What do you have to worry about diagnosing left axis deviation in prescence of inferior infarct?
LAD = big down in aVF = S
need to make sure its an S not a Q which would signal infarction
What are some causes of left axis deviation?
- left ventricular hypertrophy
- left anterior fascicular block
- LBBB
- inferior MI
- aced beats
- WPW
- primum ASD
What is extreme axis deviation?
180 to -90 degrees
What are some causes of extreme axis deviation?
- right ventricular hypertrophy
- apical MI
- VT
- hyperkalemia
What is sokolow LVH criteria?
S in V1 + R in V5 or in V6 > 35
