ECG Flashcards
Lead II is attached to which areas? What is measured in lead II?
Lead II compares the electrical activity seen from the electrodes placed on the left leg and the right arm.
What are the 2 types of leads that is used in measuring the ECG?
Chest leads and limb leads (6 of each)
How are the limb leads named?
I, II, III, aVF, aVR, aVL
How are the chest leads named?
V1, V2, V3, to V6
Which leads are looked at to investigate for axis deviation?
Leads I and aVF
Which leads are looked at to investigate for bundle branch blocks?
Leads I and II
List 6 indicators of Left anterior fascicular block
- LAD
- q1r3 (small Q wave in Lead I and small R wave in Lead III)
- Lead I: positive QRS
- Lead II: Negative QRS
- Lead III: Negative QRS
- Commonly with RBBB
List the 6 indicators of Left Posterior fascicular block
- RAD
- r1q3 (small r in Lead I and small q in Lead III)
- Lead I: Negative QRS
- Lead II: biphasic QRS (Neither negative nor positive)
- Lead III: positive QRS
In atrial tachycardia, what is the rate of atrial depolarisation?
> 150/min
AV node cannot conduct atrial rates of discharge greater than what value?
What is the consequence of this?
AV node cannot conduct atrial rates >200/min.
There will be an AV block, with some P waves not followed by QRS complexes.
What are the similarities and differences between AV block associated with atrial tachycardia, and second degree heart block?
In both AV block a/w tachycardia and second degree heart block, some P waves are not followed by QRS complexes.
However, the AV node is functioning properly in AV block a/w tachycardia. In second degree heart block associated with sinus rhythm, the AV node is not conducting normally.
What is the ECG pattern of an atrial flutter?
When there is no flat baseline between the P waves (as atrial rate is >250/min.
Does carotid sinus pressure help abolish supraventricular tachycardia or ventricular tachycardia?
Supraventricular tachycardia, it has no effect on ventricular tachycardia
What are the 3 interpretations of tachycardia with broad QRS complexes?
- Ventricular tachycardia
- Supraventricular tachycardia with bundle branch block
- Supraventricular tachycardia with Wolff-Parkinson-White syndrome
Patient has an acute Myocardial Infarction. ECG presents with tachycardia and broad QRS complexes. What is the interpretation?
Ventricular tachycardia
Describe the 4 characteristics of a normal QRS complex
- Duration is no greater than 120ms
- In a right ventricular lead (V1), the S wave is greater than the R wave
- In the left ventricular lead (V5 and V6), the height of the R wave is less than 25mm
- Left ventricular leads may show Q waves due to septal depolarisation, but these are less than 1mm across and less than 2mm deep
What is the sign of Right axis deviation and left axis deviation as shown on the ECG?
In Right Axis Deviation, the leads I and aVF are pointing together.
In Left Axis Deviation, the leads I and aVF are pointing apart.
What is the ECG pattern in right ventricular hypertrophy?
- Tall QRS complex, with the height of R greater than the S wave in lead V1.
- Deep S wave in lead V6
- Right axis deviation
- a peaked P wave due to right strial hypertrophy
- In severe cases, the T waves are inverted.
Supraventricular rhythms have broad or narrow QRS complexes? What are the exceptions to this presentation?
Supraventricular rhythms have narrow QRS complexes.
Exception occurs when there is a supraventricular rhythm with a right or left bundle branch block, or the Wolff-Parkinson-White syndrome, where the QRS complex is wide
What is the pattern of the ECG in hyperkalaemia?
Flattened P wave, sharp T wave and broadened QRS complex
