ECG Flashcards
STEMI Criteria in Men over 40
2mm in V2-V3, 1mm in all other leads
STEMI Criteria in Men under 40
2.5 mm in v2-v3, 1mm in all other leads
STEMI criteria for women, regardless of age
1.5 mm in V2-V3, 1mm in all other leads.
What classifies a STEMI on the ecg
ST elevation in 2 contiguous leads with reciprocal depression in other leads
What will you see in the initial onset of transmural ischemia
Hyper acute T wave
What is the criteria for pathological q waves?
1 small box or 0.04s wide. 2mm deep, and 25% of depth of qrs complex
What are the 3 atrial rhythms that could be present, when you have a tachycardia with no discernable p waves and irregularly irregular complexes?
MAT, Atrial Fib with RVR, Wandering Atrial Pacemaker
When you have a Tachycardic Regular rhythm, what are the 3 options it could be?
SVT, Atrial Flutter, Sinus Tachycardia
Which precordial leads look at which area of the heart? What are they supplied by?
V1 - V2 : Septal, LAD. V3-V4 : Anterior, LAD. V5-V6: Lateral (Low), LAD/LCX
Which limb leads look at which area of the heart, what are they supplied by?
1-AVL: High Lateral, LCX. 2-3-avF: Inferior, RCA. AVR: on its own, Left main, Prox LAD, 3 vessel disease
Pathologic Q Wave Criteria
0.4s or 1mm wide or greater, greater than 25% of QRS complex, 2mm deep, seen in leads v1-v3
What could peaked T waves be an indication of?
Hyperkalemia
What is important to note about which direction biphasic t waves go?
If it goes up and then down it indicates ischemia, if it goes down and then up it indicates hypokalemia
What are the characteristics of P Pulmonale, and what does it indicate?
Peaked p waves in lead 1 and v1, indicates right atrial enlargement
What are the criteria for P Mitrale and what does it indicate?
Humped p wave in lead 1 and a biphasic p in a v1, indicated left atrial enlargement.
What does a variable p wave morphology indicate?
Multifocal atrial rhythms
What is important about an inverted p wave?
Ectopic atrial or junctional rhythms
What is a normal PRI?
0.12-0.20s
What is a short pri?
Less than 0.12s
What is important to remember in the setting of a short PRI?
Could be due to a pre-excitation syndrome (WPW) or an Junctional rhythm (absent or abnormal p wave or retrograde p waves.)
What is important to remember about PR segment abnormalities? Specifically depression and elevation?
PR Depression - Pericarditis
Atrial Ischemia in the setting of MI. PR depression or elevation.
What leads would small q waves be normal?
Leads I, avL, v5-v6.
What important q wave abnormalities may be found on an ECG?
V1-V3 not normally seen, if not found in v5-v6 consider it abnormal (unless in LBBB)
What are the main points to remember when initially evaluating the QRS complex?
Narrow vs Wide
Voltage (Height)
Morphologies not to miss
What is important to realize about wide complex QRS?
Either ventricular in origin or abberantly conducted supraventricular complexes (such as BBB, Hyperkalemia or Sodium Channel blockade)
Narrow QRS morphology origins?
SA node -> NSR
Atria —> abnormal p waves / flutter waves / fibrillatory waves
AV node/Junction -> absent p wave or PRI less than .12
Wide Complex Criteria?
Greater than .10 = abnormal
Greater than .12 = BBB or Ventricular Rhythm
Left Ventricular Hypertrophy Criteria?
S wave in v1-v2 + R wave in v5-v6 = 35 mm or greater.
Voltage criteria must be accompanied with some leads that have non-voltage criteria.
Left Axis Deviation
ST depression and TWI in lateral leads
Right Ventricular Hypertrophy Criteria
Right Axis Deviation
Dominant R Wave in V1 (>7mm tall or R/S ratio >1)
Dominant S Wave in V5 or V6 (>7mm deep or R/S ratio <1)
QRS less than 120 ms
Right Ventricular Strain Pattern Criteria? Associated Features of it?
ST depression and TWI in leads corresponding to R ventricle:
R Precordials - V1-V3 +/- V4 and Inferior leads often most pronounced in lead III.
Associated Features: R Axis Deviation, Dominant R wave in V1 Dominant S wave in V5-V6
What could be the causes of R Ventricular Strain Pattern?
Pulmonary HTN
Mitral Stenosis
Pulmonary Embolism
Cor Pulmonale (Chronic Lung Disease)
Congenital Heart Disease (Pulmonary Stenosis, Tetrology of Fallot)
Arrhythmogenic Right Ventricular Dysplasia
Left Ventricular Strain Pattern?
ST Elevation V1-V4 with deep S wave
ST depression and TWI in V5-V6
Generally proceeds from most elevated V1/V2 to most depressed V6.
RBBB Criteria?
QRS > 120ms
RsR’ in V1-V3 (“M shaped QRS Complex)
Wide slurred S wave in lateral leads (I,avL, V5-V6)
LBBB Criteria?
QRS > 120ms
Dominant S wave in V1
Broad monophasic R wave in the lateral leads (I, avL, V5-V6)
Absence of Q waves in lateral leads
Prolonged R wave peak time in V5-V6.
STE and upright T wave in leads with negative qrs complex or dominant S wave
STD and TWI in leads with positive qrs complex or dominant R wave
Potential Causes of Wide Complex QRS?
BBB
Hyperkalemia
Sodium channel blockade (TCA’s)
Pre-Excitation (WPW)
Ventricular pacing
Hypothermia
Intermittent Aberrancy
Electrical Alternans
QRS complex alternate in height
Due to massive pericardial effusion (the heart swinging back and forth in the pericardial sac causes the changes in voltage on the ecg)
Morphologies important to immediately spot in the QRS complex?
Brugada -> Partial RBBB with STE in V1-V2
WPW -> Short pr, delta wave
TCA poisoning -> wide QRS and dominant R in AVR
What happens to the QT in relation to changes in heart rate?
Shortens as the HR increases
Lengthens as the HR decreases
What does prolonged QT increase the risk of?
Ventricular arrhythmias specifically TdP
What does shortened QT syndrome increase the risk of?
Paroxysmal atrial and ventricular fib and sudden cardiac death
Prolonged Qtc criteria in men and women?
Men > 440ms
Women > 460ms
What is important to note when the QTc is greater than 500ms what does it increase the risk of?
Torsades de pointes.
What is the criteria for shortened QT?
Anything less than 350ms
What is a rule to remember to decipher normal QT?
Normal QT is less than half of the preceding R-R interval
Causes of prolonged QTc
Hypokalemia
Hypomagnesaemia
Hypocalcemia
Hypothermia
Myocardial Ischemia
ROSC post arrest
Increased ICP
Congenital Long QT syndrome
Meds (Anti Psychs, TCA’s, Anti Depressants, Anti-Histamines)
Causes of Short QTc
Hypercalcemia
Digoxin Effect
Congenital Short QT
What is a J wave or Osborne wave? What does it indicate?
Any positive deflection that occurs before the J point. Indicates hypothermia.
Where would you see elevation of the J point?
STE in infarction processes or other abnormalities, BER.
Types of Narrow Complex Tachycardias?
AF, Atrial flutter, sinus tach, AVNRT, AVRT
Types of Wide Complex Tachycardias?
VT, SVT with abberancy, svt with pre-excitation (WPW)
What is the score used in AF to determine stroke risk?
CHADS VASC score
ECG Features of Atrial Flutter?
Narrow complex tach, can be reg or irreg depending on conduction, commonly a 2:1 block, flutter waves or saw tooth pattern best seen in leads 2,3, and avf, it may resemble p waves in V1.
ECG Features of WPW
Short PR, delta wave, wide QRS, ST and T wave changes.
What are the common ecg features of AVNRT?
Narrow complex, regular, fast, absent p waves.
What is important to remember about a wide complex tachycardia with hemodynamic compromise?
VT until proven otherwise
What is a fusion beat?
A supraventricular and ventricular impulse connect to form a hybrid complex of half normal half wide. They are seen in VT when the odd intrinsic impulse is conducted at the same time as ventricular impuse and are used to differentiate SVT with abberancy vs VT.
What is a capture beat?
When a atrial impulse happens to fire at the right comment to be conducted and produce a normal looking complex in the presence of VT. Used to diagnose VT.
The findings seen on the ecg that confirm VT over SVT with abberancy?
AV dissociation
Fusion Beat
Capture beat
extreme axis deviation (both negative)
ECG features of PE?
RAD, Sinus tachycardia, RBBB pattern, RV strain pattern (TWI and ST depression v1-v4)
ECG findings in Pericarditiis?
Wide spread ST elevation with concave up, pr depression, tp down sloping AKA spodicks sign
Hyper K ECG features?
Peaked T waves, p waves originally are flattened and widened with lengthened PRI, as potassium elevates p waves disappear and QRS widens a conduction block is noted.
What is important to remember about sine waves?
If noted your patient has progressed to life threatening hyperkalemia and they are peri arrest
ECG features of Hypokalemia?
U waves noted after the T, tall and wide p wave, prolonged PRI, TWI and flattening, st depression, apparent long qt (fusion of t and u waves).
What are we worried about in Long QT syndrome?
R on T phenomenon from an ectopic beat
What is a prolonged QTC?
Men 440ms
Women 460ms
What is scary about a qt of greater than 500ms
High risk for development of Polymorphic VT or TdP.
What should we check for on the ECG in every syncopal patient?
Ischemia, Arrhythmia, HOCM, Brugada, WPW, Long QT
HOCM ECG features?
dagger like q waves (especially in lateral leads) high voltage (ie hypertrophy).
What is significant of a flipped T wave in AVL? Where would it be considered to be normal?
Can be early sign of inferior MI. T wave in avL should be upright.
Considered to be normal in RBBB and LVH with strain (1 and avL)
What does the check mark sign signify?
Qrs complexes that lead straight into the T wave looks like a check mark. High degree of suspicion for stemi or early signs of ischemia
What are non specific T wave changes or inversion? When is it considered a true T wave inversion?
Less than a mm or flattening is non specific T wave changes, true inversion needs to have more than a 1 mm in the inversion.
What are non specific ST changes?
St segment is depressed but is less than 1mm this is non-specific changes, provide no diagnostic value. It has to be depressed more than 1 mm to be considered an ischemic change.
If you see profound STE in V1-V2 and AVR what are you suspecting?
Hyper K or a PE
Best leads for evaluating atrial flutter and what direction would you find the waves?
2,3, avf negative waves. V1 positive waves
What should be one of your differentials with a rate bang on 150 or +- 20
Atrial Flutter
What should be thought of in a patient with a ventricular rate over 250?
Accessory pathway existence
What can sudden episodes of uncontrolled afib cause?
SOB, chf, dizziness, palpitations, syncope, chest pain
What are the mimics of VT?
Toxicology and Metabolic Causes - TCA’s and Hyper K
— HR is usually too slow (Below 130) or QRS complexes very wide
Massive STE
- Look in all leads for: Narrow QRS and reciprocal changes. If you see a triangle like QRS must evaluate for possibility of STEMI.
What should be your differentials when you come across a TWI?
CAD, Pulmonary (PE, PNEUMOTHORAX, PNEUMONIA,), STRAIN LVH OR RVH, PERICARDITIS OR MYOCARDITIS.
ECG findings associated with PE (Must know)?
-TWI in right precordials
- STE and Depression: especially STE in V1-V2, aVR, III.
-Right Heart Strain (Right axis, tall R wave in V1 or IRBBB)
-Tachycardia (sinus or AF)
What should we be concerned about if we find flipped t waves in our inferior and anteroseptal leads?
Massive PE.
What would be more indicative of LV with strain vs an ischemia pattern?
Downsloping ST depression vs horizontal or upward.
When are T waves considered abnormal?
When they are 2/3 or above the height of the preceding R wave.
What are tall T waves associated with?
Ischemia, Infarction, CNS events, Hyperkalemia
Differentials for wide QRS?
BBB
WPW
Pacer
Metabolic (acidosis, HyperK)
Sodium Channel Blockade
Ventricular Ectopy or VT
Non specific IVCD
