ECG Abnormalities Flashcards
How does atrial fibrilation appear on an ECG?
- No P waves
- Ireggeulary irregular R-R intervals
- Normal QRS (not all conducted through AV node)
Due to origionation of impulses from multiple atrial foci.
What are the types of heart block?
1st degree 2nd degree (type 1 and 2) Third degree (complete)
How does First degree heart block appear on an ECG?
- Normal P wave
- Followed by QRS complexes
Greater than .2 seconds
How does Second degree type 1 AV block appear?
-Successivly longer PR intervals untill a QRS complex droopped
Electrial signal not conducted through AV to ventricles (dropped beat)
How does second degree type 2 heart block appear on an ECG?
- PR interval not lengthened
- Sudden dropped QRS comolex
P waves (artial rhythm) regualr Ventricular rhythm irregualr
How does 3rd degree heart block appear on an ECG?
Artia and ventricles depolarising independantly (AV conductance failure)
- Wide QRS complex
- No link between P waves and QRS complexes
How does Ventricular fibrilation appear on an ECG?
- Abnormal, chaotic and vast ventricular depolarisation
- Ventricles quiver
Impusles from ectopic sites in ventricles
No coordinated contaction/ CO
How do ventricular ectopic beats appear on an EGC?
- Wide QRS complex
- No preceeding P wave
Premature ventricular ectopic beats (PVCs)
When does ventricular tachycardia occour?
When there is a run of 3 consecutive PVCs
What does polymorphic Vtach look like?
- Gradual change in amplitude of QRS complexes
- QRS complexes twisting around an iselectric point
How does an ECG change in hypokalamia?
- Increased amplitude and width of P wave
- Prolonged PR interval
- T wave flattening and inversion
- ST depression
- U waves
How does an ECG change is hyperkalaemia?
- Tall T waves
- Loss P wave
- Widening QRS complex
- QRS continues to widen
When does ST elevation occour?
Complete occlusion of coronary artery
Full thickness myocardium involved
ST segement Elevation MI (STEMI)
What are the ECG changes on a STEMI?
- Tall peaked T waves (early)
- ST elevation (above isoelectric point in leads facing damaged area)
Short vs long changes in STEMI ECG?
Acute;
- Hyper actute T waves to T wave inversion
- ST elvations (goes in days)
- ST depressions (normally resolve with time
Chronic;
-Pathological QRS complesex arise
What are ECG changes in a non STEMI?
- ST segment depression
- T wave inversion
What ECG changes occour in ischeamia (unstable angina)?
- ST segment depression
- T wave inversion
Same as non STEMI
What ECG changes occour in stable angina?
- ST depression during exercise
- ECG changes reverse at rest
- (down sloping of St segment depression/elevation)
What changes ECG occour as result of previous MI?
Pathological Q waves
Negative deflection preceding R wave
No electrical activity in dead tissue
No apots in dead tissue
ECG looks though dead tissue (picks up electrical activity from opposite side of infarct)
How to tell the difference between ischeamia/ non STEMI?
Blood tests
Troponin present in non STEMI but not in icheamia
How to tell area of heart effeted on STEMI ECG?
Damaged tissues come towards electrode
How to tell area of heart affected in non STEMI/ischaemia?
Abnormal current transversing damaged tissue is moving away from recording electrode
