1. Regularity/Rhythm
Do the QRS complexes come at a regular interval?

2. Regular rhythm with a P wave before each complex: SINUS RHYHTM
Irregularly irregular rhythm: ATRIAL FIBRILLATION
Regular rhythm but with no p waves: ATRIAL FLUTTER
Regular but long PR interval: FIRST DEGREE HEART BLOCK
Regularly irregular: SECOND DEGREE HEART BLOCK
Regular with no clear complexes: VENTRICULAR TACHYCARDIA
Irregular and disorganised: VENTRICULAR FIBRILLATION

3. PR INTERVAL GREATER THAN 220ms!

4. QRS (less than 120ms-number of small squares x 40)
Morphology
Do all complexes look the same?
Are all complexes the same duration?
QRS (less than 120ms-number of small squares x 40)
P wave (Less than 120ms)

5. Broad QRS morphology: BUNDLE BRANCH BLOCK
NORMAL ECG
RIGHT BUNDLE BRANCH BLOCK
‘RSR’ pattern
LEFT BUNDLE BRANCH BLOCK
Deep S waves

6. BBB happens with every complex, ectopic's come and go **
Different morphology to the normal sinus beat however it is not a bundle branch block even though it may look like it!
BBB happens with every complex, ectopic's come and go **
These are just extra heart beats that originate from somewhere else in the heart (the ventricles or somewhere other than the SAN in the atria)
Can have ventricular ectopic's which are known as VEs or PVCs
Can also have atrial ectopic's which are known as SVEs or PACs : these will look the same as a normal beat!!
These beats can either occur on their own (isolated ectopic) or in pairs (Couplets) or in threes (triplets), etc..

9. ST Segments ST elevation- STEMI ST Depression- Angina
Indication of heart attacks (Myocardial infraction)
ST elevation- STEMI
ST Depression- Angina