ECG Review Flashcards
determining HR
- 300 / # big boxes
- 300, 150, 100, 75, 60, 50
determining limb lead axis
- lead I and aVF + = normal (0 to +90)
- lead I and II + = normal (-30 to +90)
- find isoelectric lead; axis = 90˚ of that lead
precordial lead axis
- QRS predominantly negative in V1 and positive in V6
- isoelectric transition point around V3 or V4
normal intervals:
- PR interval
- QRS interval
- QT interval
- Q wave
- 3-5 small boxes
- ≤ 2 small boxes
- 2 large boxes, less than half of RR interval
- 1 small box wide or deep (except aVR)
sinus tachycardia
- positive p wave before QRS (I, II, aVF) [normal]
- HR > 100
sinus bradycardia
- positive p wave before QRS (I, II, aVF) [normal]
- HR < 60
atrial fibrillation
- no positive p wave before QRS
- irregularly irregular narrow QRS intervals
- lumpy bumpy baseline
atrial flutter
- no positive p wave before QRS
- sawtooth pattern
- narrow but regular QRS
- 2:1 block -> HR~140
- 4:1 block -> HR~70
supraventricular tachycardia
- no positive p wave before QRS
- regular narrow QRS
SVT due to AVNRT
- baseline ECG in sinus rhythm shows narrow QRS and normal PR
SVT due to AVRT
- baseline ECG in sinus rhythm has delta wave and short PR
ventricular tachycardia
- no positive p wave before QRS
- wide QRS tachycardia
monomorphic VT
- QRS complex same shape
- reentry arrhythmia from area of ventricle
polymorphic VT
- multiple QRS shapes
- acute ischemia, meds prolonging QT
- Torsades de Pointes
atrial fibrillation treatment
- structurally normal heart: type IC a-a
- structurally abnormal: type III a-a
- ablation procedure (pulmonary vein)
atrial flutter treatment
- very responsive to ablation (cavo-tricuspid isthmus)
AVNRT treatment
- adenosine slows AV node conduction
- AV node blockers
- slow pathway ablation
AVRT (WPW) treatment
- bypass tract ablation
- *AVOID AV node blockers
LBBB
- wide QRS at sinus rhythm, p wave present
- V1 goes down
RBBB
- wide QRS at sinus rhythm, p wave present
- V1 goes up, rabbit ears
1˚ AV block
- p wave always followed by QRS
- PR interval > 5 small squares
- delay usually at AV node
2˚ AV block type I/Mobitz I/Wenckebach
- lengthening PR intervals before blocked P wave
- PR interval following blocked wave is shorter than PR interval before
- block high in AV node
2˚ AV block type II/Mobitz II
- fixed prolonged PR intervals before/after blocked P wave
- block on his-purkinje system
- can progress to AV block
3˚ AV block
- all P waves blocked
- P wave rate different than QRS rate (distance variable)
- QRS narrow = high block
- QRS wide = low block
NSTEMI
- acute: ST depression and/or T wave inversion
- weeks later: normal ST and T; NO Q waves
STEMI
- acute: ST elevation
- hours: ST elevation, decreased R wave, Q wave
- 1-2 days: T wave inversion, deeper Q wave
- more days: ST normal, T wave inversion
- weeks: ST/T normal, Q wave persists
anterior STEMI
- ST elevation in leads I, aVL, V2, V3, V4
- LAD artery
- may sig reduce LV systolic function -> HF
inferior STEMI
- ST elevation in leads II, III, aVF
- PDA (90% RCA)
- GI symptoms common, nitro induced hypo, bradycardia from vagus
- proximal RCA occlusion can cause RV infarction
LVH
- increased QRS amplitude in V1 + V5, aVL, or I
- caused by: AS, HTN, HCM
low voltage
- caused by anything that reduces electrical impulse conduction
- amyloid
types of bradycardia
- sinus pauses (treatment > 3 sec)
- sinus bradycardia (HR < 60; pathologic and physiologic)
bigeminy
- alternating normal and premature beat
premature atrial contraction
- supraventricular
- preceded by p wave
- narrow QRS
- may not conduct to ventricle
- resets SA node
premature ventricular contraction
- ventricular
- no p wave
- wide QRS
- may not conduct to atrium
- no effect on SA node
