Flashcards in ECGs Deck (45):
What leads show Inferior surface of Ventricles ?
2,3 and aVF
What leads show RV and Septum?
V1 and V2
What leads show AS of Ventricles?
V3 and V4
What shows IV septum and AS of Ventricles ?
V1 to V4
What shows lateral surface of ventricles ?
1, aVF , V5 and V6
What shows upward deflection?
Depolarisation to the positive end or repolarisation away
What shows Downward deflection ?
Depolarisation to the negative end or repolarisation toward
Which parts of the Conduction system show flatline?
SAN and AVN depolarisation, Bundle of his and fibrous ring and ST segement.
What does P wave show?
What does QRS complex Show?
What does T wave show?
What special feature does AVN do?
Delays conduction to allow Atrium to empty
How long is PR interval and where ?
3-5 small boxes, Start of P to start of QRS.
What is slower and fast sinus rhythm?
Sinus Tachycardia and Sinus Bradycardia
What is Atrioventricular conduction blocks?
Delay/ Failure of impulse conduction from atrium to ventricle via AVN and BOH.
What is 1st degree Heart Block?
Increased PR interval , more than 5
What is Mobitz 1 degree or Wenckenbach Heart block?
PR interval successively longer until QRS dropped
What is Mobitz 2 Heart Block?
No PR interval longer and sudden QRS drop.
High risk of complete HB
What is 3rd Degree Heart block?
Failure of AV conduction
Atrium and ventricles are independently depolarising
Ventricular Escape rhythm is slow
Why is 3rd Degree dangerous ?
Too slow to maintain BP
What is shown is bundle brach block?
Wide QRS due to longer ventricular depolarisation
What is affected in supraventriuclar?
AV and SA node
What is affected in Ventricular ?
What is main characteristic if irregular ventricular rhythms?
Wide QRS complexes
What can cause atrial fib?
Thyrotoxicosis and dilation
What is main features of Atrial Fib?
irregular R-R interval
Random rapid impulses
What is ventricular Ectopic beat?
Ectopic foci in ventricl muscle - random
No impulse in his purkinje system
What is the definition of VT?
Run of 3 or more Ectopic beats and can lead to VF
What is VF?
Chaotic fast ventricular depolarisation.
No CO - leads to cardiac arrest
What is seen in Supraventricular Tachycardia?
No P waves
What part of heart is injured in partial occlusion?
Which part of the heart is injured in full occlusion ?
Epicardium - Visceral layer
What is seen in full occlusion?
What are the ECGs seen at Acute, hours , 1-2 days, Days later and finally weeks?
Acute: ST Elevation , R decreases
Hours: Q wave begins
1-2 days: T wave inversion , Q Wave deeper
Days later: ST Normalises , T inverted
Weeks: Q wave persists
Why does Q wave show muscle necrosis in the leads it is facing ?
Dead muscle cannot conduct
Electrode looks at other impulses
Describe a pathological Q wave ?
> 1 small box wide
>2 small deep
What is seen in an old MI?
Normal ST but pathological Q waves
What diagnosises can be made by ST depression and T wave insertion ?
Stable angina - when under exercise
Non Stemi MI
How can you differentiate between ischemia and Non STEMI MI ?
Blood test for troponin C
What causes the less excitability in heart ?
Hyperkalemia - RMP less negative
Inactivation of Na+ channels
What are the changes in the ECG for Hyperkalemia?
1. tall T waves
2. Flatten P wave , Widen PR
3. Widen QRS and no P wave
4. QRS and T wave merge
What are the changes in ECG for hypokalemia?
1. Flatten T wave
2. Taller U wave
3. ST depression
What are the 5 coronary arteries for the AS ?
RCA, LCA, LMA, RMA and LAD
What is the coronary artery for the posterior right side?
Posterior intraventricular artery - Plv