U waves Flashcards
1
Q
U wave definition
A
small 0.5 mm deflection
same direction as T wave
2
Q
Normal U wave
A
same direction as T wave size inversely proportional to HR - increases as HR slows down normal voltage < 25% of T wave max normal amplitude= 1-2 mm
3
Q
Prominent U Wave
A
> 1-2 mm
> 25% height of T wave
4
Q
Prominent U wave DDx
A
severe Hypokalemia Hypocalcaemia Hypomagnesemia Hypothermia Raised Intracranial pressure L Ventricular Hypertrophy Hypertrophic cardiomyopathy
5
Q
Prominent U waves: secondary to DRUGS
A
Digoxin
Phenothiazine
Class Ia antiarrhythmic: quinidine/ procainamide
Class III antiarrhythmic: sotalol/ amiodarone
6
Q
Inverted U wave
A
inversion abnormal in lead with upright T wave
negative U highly specific for presence of heart dz
7
Q
Inverted U causes
A
Coronary artery disease HTN Valvular Heart Disease Congenital Heart Disease Cardiomyopathy Hyperthyroidism
8
Q
Inverted U and Chest Pain
A
very specific Myocardial Ischaemia
earliest marker unstable angina evolving MI
predict ≥ 75% stenosis of LAD/ LMCA & LV dysfunction
