ECG Pearls Flashcards
(48 cards)
Findings suggestive of PE (11) on ecg
- Sinus Tachycardia (44% pts)
- Incomplete or complete RBBB (18% pts)
- ST depression V1-3
- T wave inversion in V1-3, and inferior leads (34% pts)
- S1Q3T3 - not sen or spec
- RAD - 16% pts
- Dominant R wave in V1
- RAE - peaked P wave II>2.5mm (9% pts)
- CLockwise rotation - shift of R/S transition point towards V6
- Atrial tachyarrythmias - AFL, AFIB
- Non spec ST changes - 50% pts
Criteria for Brugada Syndrome
- Type 1: coved STE >2 mm in greater than 1 of V1-V3 followed by negative T wave.
- only ecg finding thats potentially diagnostic - called Brugada sign
What is Wellens?
Inverted or Biphasic T waves in V1-V3 indicating critical LAD occlusion
- Extremely high risk for extensive anterior wall MI within next 2-3 weeks
Type A: Deep symmetrical inverted T waves
Type B: Biphasic T wave with initial deflection +ve and terminal deflection negative.
What to look for when Syncope Patient (9)
On ecg
- Long QT
- Brugada Syndrome (Coved STE V1-3, TWI)
- Tachy/Brady Arrhythmia
- 2nd type II or 3rd deg HB
- WPW
- HOCM
- ACS
- arrhythmogenic right ventricular dysplasia (epsilon waves)
- PE
Scarbossa’s Criteria (MI in LBBB)
- Concordant STE >1mm in any lead with +ve QRS (5pts)
- Concordant STD >1mm in V1-V3 (3 pts)
- Excessive discordance STE >5mm (2pts)
>3 points = 90% specificity for MI
- need 3 or more points.
What is a sign of left main critical stenosis? On ecg
STE aVR
WPW ECG changes
- PR interval shortened
- Delta wave
- ST segment and T wave discordant changes
- Pseudo infarction pattern can be seen in 70% pts. due to negatively deflected delta waves in inf and ant leads (pseudo Q waves) or as a prominent R wave in V1-3 mimicking posterior infarction.
What are causes of LAD on ECG (3 main)
- LVH
- LAFB, LBBB
- Inferior MI (look for Q waves in inf leads)
- Pregnancy/obesity
What is the definition of Wide QRS?
How wide does the QRS have to be to be a BBB?
> 110ms
>120 ms
Causes RAD (11)
Left posterior fascicular block Lateral myocardial infarction Right ventricular hypertrophy Acute lung disease (e.g. PE) Chronic lung disease (e.g. COPD) Ventricular ectopy Hyperkalaemia Sodium-channel blocker toxicity WPW syndrome Normal in children or thin adults with a horizontally positioned heart Dextrocardia
On ECG what is a normal P wave morphology in V1 and II?
Biphasic in V1, Positive in II and avF
On Ecg if wide QRS> 160 what 4 causes should you think of?
- Hyperkalemia
- Na channel blockage (give NaHCO3)
- Acidosis
- Intra-ventricular conduction delay (Bifasicular or trifascicular blocks)
What is Basset’s formula to calculate QTc?
QTc= QT/ square root (R-R interval)
However, this is a non-linear formula, obtained from data in only 39 young men, is not accurate, and over-corrects at high heart rates and under-corrects at low heart rates.
On ecg: what do you see in RAE? (P-pulmonale)
Peaked P wave with amplitude:
>2.5 in inf. leads (II*, III and aVF)
>1.5 mm in V1, V2
What ECG changes do you get with Hyperkalemia? (5)
- Peaked T waves
- Flat P wave
- Long PR
- Elevated ST
- Sine wave –>VF
What is the normal length of QT?
and how do you measure it?
QTc is prolonged if > 440ms in men
or > 460ms in women
QTc > 500 is associated with increased risk of torsades de pointes.
Measured from start of Q wave to end of T.
What are the ECG changes in Hypokalemia? (6)
- Flattened T wave and inversion
- Incr amplitutde of P wave
- Prolonged PR interval
- ST depression
- Promiment U waves (usu in precordial leads)
- Apparent Long QT (due to fusion of T and U = long QU interval)
What are ECG changes in pericarditis? (5)
- Diffuse STE (usu all except v1)
- Concave STE (smiley face)
- Elevation not >5mm
- PR depression in V6,II (specific)
- PR elevation in aVR = “knuckle sign”
- No Q waves or reciprocal changes
What are the ECG stages/evolution in pericarditis?
STE and PR depression
ST resolution
T wave inversion
Normalization
BER vs Pericarditis? What do you look for?
Pericariditis
- Generalized STE
- PR depression
- No fish hook - J point notch
- Normal sized T waves
- ST/T>0.25 (highly specific)
BER
- STE in precordial leads v2-V5
- No PR depression
- “fish hook” - j point notch
- Big T-waves
- ST/T <0.25 (b/c of big t waves)
What is Amal Mattu’s 3 steps to differentiate STEMI from pericarditis?
- Look for ST depression (other than aVR and V1)- there should not be any reciprocal changes in Pericarditis
- Morphology of ST segment. Smiley face in pericarditis, frown face/tomb stone in STEMI
- STE III>II –> this is highly specific for MI
Then look for PR depression. But remember PR depression and PR elevation in aVR can occur in STEMI if there is atrial ischemia
What is criteria for RBBB? What are associated features?
Diagnostic Criteria
- Broad QRS > 120 ms
- RSR’ pattern in V1-3 (‘M-shaped’ QRS complex)
- Wide, slurred S wave in the lateral leads (I, aVL, V5-6)
‘MaRRoW’ (V1, V6)
Associated Features: ST depression and T wave inversion in the right precordial leads (V1-3)
Variations: Sometimes rather than an RSR’ pattern in V1, there may be a broad monophasic R wave or a qR complex.
What is an incomplete RBBB?
Incomplete RBBB is defined as an RSR’ pattern in V1-3 with QRS duration < 120ms.
It is a normal variant, commonly seen in children (of no clinical significance).
What are causes for RBBB? (3)
- Right ventricular hypertrophy / cor pulmonale
- Pulmonary embolus
- Ischaemic heart disease
- Rheumatic heart disease
- Myocarditis or cardiomyopathy
- Degenerative disease of the conduction system
- Congenital heart disease (e.g. atrial septal defect)