EKG associations Flashcards
QT interval length
Due to the effects of heart rate, the corrected QT interval (QTc) is frequently used. The QTc is considered prolonged if greater than 450 ms in males and 470 ms in females
How to quickly see if QT is prolonged?
A quick way to distinguish a prolonged QT interval is to examine if the T wave ends beyond the halfway point between the RR interval. If the T wave ends past the halfway point of the RR interval, it is prolonged.
What’s a sign of limb lead reversal (switching l and r arms)
Whenever you see a negative P wave and QRS complex in lead I the likely diagnosis is limb lead reversal.
What is the differential for ST elevation?
always consider myocardial infarction first when you see ST elevations, but don’t forget the differential diagnosis of ST elevations not only includes 1) ischemic heart disease (MI, Prinzmetal angina, ventricular aneurysm) but also 2) pericarditis, 3) left bundle branch block (LBBB) (in V1-V3) and 4) normal (“early repolarization”) variant (J point elevation).
What are other signs of pericarditis besides diffuse ST segment elevation?
signs of subepicardial atrial injury: PR elevation can be seen in aVR and PR depression is best seen in II, aVF, V4-V6.
When do you use Scarbossa’s
when LBBB and trying to diagnose MI
What are 3 criteria for Scarbossas
1) ST segement elevation 5mm or more that is discordonant with WRS
2) ST segment depression of 1mm or more in any lead V1-V3
3) ST segment elevation of 1mm or more iconcordant with QRS in any lead
Ddx for diffuse ST elevation
ischemic heart disease
pericarditis
LBBB
early repol (normal)
What is dx for positive troponin in absence of ischemic heart disease?
PE, myocarditis, TAkatsubo
type II MI - tachyarrtymias, shock, HTN emergency, cocaine
low voltage EKG ddx
infilitrative CM
pulm disease
hypothyroid
pericardial effusion
when QRS amplitude < 5mm limb leads
when QRS amplitude < 10mm in precordial leads
electrical alternans
alternate QRS amplitude change – happens with pericaridal effusion as heart is swinging back and forth in sac
QTc change - when to be concerned with a new drug?
when post-drug baseline Qtc prolongs by more than 60ms from baseline, and also > 500 ms
Brugada EKG sign
Coved ST segment elevation >2mm in >1 of V1-V3 followed by a negative T wave.
This is the only ECG abnormality that is potentially diagnostic.
What clinical criteria must accompany Brugada syndrome?
This ECG abnormality must be associated with one of the following clinical criteria to make the diagnosis:
Documented ventricular fibrillation (VF) or polymorphic ventricular tachycardia (VT).
Family history of sudden cardiac death at <45 years old .
Coved-type ECGs in family members.
Inducibility of VT with programmed electrical stimulation .
Syncope.
Nocturnal agonal respiration.
