ECG Flashcards
ECG Voltage criteria for left ventricular hypertrophy (LVH)
S wave in V1 + R wave in V5 > 35mm (note there are many different ways of measuring voltage criteria for LVH)
When should you NOT used adenosine in a SVT?
if wide complex QRS. Could be an AVRT going in the bad direction and by shutting off the AV node for a second you can actually destabilize them..
Electrical alternans refers to a beat-to-beat variation in the QRS complex height, with alternating taller and shorter QRS complexes.
What diagnosis do you need to rule out?
Tamponade - Massive pericardial effusion
ECG signs of Right Ventricular Hypertrophy (RVH) or RV strain
Right ventricular strain is a REPOLARIZATION abnormality due to right ventricular hypertrophy (RVH) or dilatation.
ST depression and T wave inversion in leads corresponding to the right ventricle:
- Right precordial leads V1-3 +/- V4
- Inferior leads (II, III, aVF) often most pronounced in lead III as this is the most rightward facing lead
- dominant R wave in V1 (good one, simple yes/no dx)
- right axis deviation
ECG features of hyperkalemia (4)
- immediate management?
- peaked T, p wave flattening, PR prolongation, QRS widening (can have bradycardia)
Imagine/visualize that the T wave is “pulled upwards”, creating tall “tented” T waves, and stretching the remainder of the ECG to cause P wave flattening, PR prolongation, and QRS widening.
CaLcium gluconate 2g IV to stabilize myocardium, then shift, then get rid of K…
ECG features of hypokalemia (3)
Hypo=low.. Imagine pushing down on the T
Widespread T wave flattening/inversion that also looks like ST depression
Prominent U waves (best seen in the precordial leads V2-V3)
Apparent long QT interval due to fusion of T and U waves (almost looks like a sine wave)
Immediate treatment for torsades?
A rapid IV bolus of magnesium 2g is a standard emergency treatment for torsades de pointes
If you shock them, they may convert but will just go back into torsades because you haven’t fixed their long QT
“Classic” ECG change of a PE causing RV strain?
S1Q3T3 (“SI, QIII, TIII”) - deep S wave in lead I, Q wave in III, inverted T wave in III (20%).
This “classic” finding is neither sensitive nor specific for PE.
Could also see right axis deviation.
Most common ECG finding in patient with a PE?
Sinus tachycardia :)
Ddx for right axis deviation
pulmonary hypertension
PE
cor Pulmonale
What is the PAILS mnemonic for?
Bonus: what letter has a caveat?
Tells you where to look for reciprocal change
- ST segment elevation in a group of leads most commonly creates reciprocal changes in the leads that are represented by the next letter of the mnemonic
- eg Anterior ST elevation, look for Inferior reciprocal depression
Bonus: Lateral ST elev look for inferior or septal depression
If there is elevation in anterior leads, which leads do you look for reciprocal depression in?
Inferior leads (II, III, aVF)
If you see ST depression in V3 and V4, what do you need to think about? What do you do next?
posterior STEMI
get a 15 lead ECG
What leads are I, aVL?
Lateral leads
Anterior/septal leads?
Septal leads (V1, V2) Anterior leads (V3, V4)
