SOURCE – NIKHIL MARVA TEXTBOOK

P Wave

•Positive wave

• Shape is up rounded deflection

• Cause: Depolarisation of atrial musculature.

• Duration: 0.1 sec

• Intensity: 0.1-0.12 mV

• Represents functional activity of atria.

Clinical Aspects:

1 Mitral stenosis: left atrium is hypertrophied and P wave is larger and prolonged.

2 Tricuspid stenosis: Right atrium is hypertrophied and P wave is taller but there is no change (normal) duration.

3 Atrial fibrillation: P wave disappears and is replaced by fine irregular oscillations.

4 Ectopic Pacemaker: (reverse) The impulses are sent from AV node to SA node.

QRS COMPLEX

• Q wave is often absent.

• Cause: Ventricular Depolarisation.

• Duration: 0.08 sec ( less than P wave)

• Intensity: 0.1 mV to 0.2 mV ( amplitude is more)

• R wave is 1 mV

• S wave is 0.4 mV

• Total Intensity is 1.5 mV to 1.6 mV

Clinical Aspects

1 Deep Q wave: more than 0.2 mV. This is seen Myocardial Infarction.

2 Tall R wave: more than 0.1 mV. This is seen in ventricular hypertrophy.

3 Low Voltage QRS Complex:  This is related to hormones and pericardial fluid. Hypothyroidism and Pericardial fluid around the heart.

4 QRS COMPLEX: Prolonged in bundle branch block.

T wave 

• Cause: Ventricular Repolarization.

• It’s positive wave because the direction of Ventricular repolarization is opposite to depolarization.

• Duration: 0.27

• Intensity: 0.3 mV

Clinical Aspects

1 Flattened T wave: old age.

2 Height increases: during exercise.

3 Inverted T wave: this is seen in myocardial infarction.

4 Tall and peaked T wave:  Hyperkalaemia.

U wave

• Positive round wave

• Repolarization of papillary muscled

• Duration: 0.08 sec

• Intensity: 0.2 mV

• Rarely seen

• Prominent in hypokalaemia.

P R interval 

• Onset of P wave to onset of QRS complex (PQ interval)

• Represents AV conduction time.

• Duration: 0.12 to 0.21 sec

Clinical Aspects

1 Prolonged PR interval: AV conduction block.

J Point 

• The meeting point of QRS complex with ST segment.

• It represents the end of Depolarisation and beginning of repolarization.

• At this point, no current flows around heart.

– Written by Anisha Valli

Hey everyone!
We are launching the Dentowesome Author Internship (DAI) program for this month! If you have wanted to contribute or write about dentistry but you haven’t been able to – this is your chance! 🙂  

For this project, you can write mnemonics and small posts. After submitting 25 articles, you will be awarded with certificate 🙂 

But to participate in the Dentowesome Author Internship (DAI) program you must have:
1. Ideas (whether it be cool facts, mnemonics or presenting a usual fact in an unusual way – I will help you out with this.)

2. Willingness to write on a timely basis (because ideas not brought to a reality are no fun!)

If you are interested, email me on dentowesome@gmail.com with “DAI” in the subject and we can take it forward from there 🙂

I am so excited about this!!! 😀  

PS: At the end of the project, if you enjoy being a guest author and you wish to continue with us, you’re always welcome to join the team and be a permanent author.