ECG question

[janis]

in ECG, the RR interval is different during inspiration and expiration. Can anyone explain it to me? thank a lot:nod

[youngyew]

Haha SPM and STPM?!

RR interval (the interval between two different heartbeats) is different during inspiration and expiration and this effect is more marked in young people. Typically the heart rate is faster during inspiration and slower during expiration.

This is what UpToDate (http://www.uptodate.com) says:
Respiratory sinus arrhythmia results from changes in autonomic tone during the respiratory cycle. Inspiration reflexively inhibits vagal tone, thereby increasing the sinus rate. With expiration, vagal tone rises to its previous state, and the rate declines. This type of sinus arrhythmia disappears with breath holding. However, stimulation of the carotid baroreceptors by neck suction during breath holding will restore sinus arrhythmia, suggesting that the autonomic changes responsible for sinus arrhythmia can also be due to baroreflex stimulation. Baroreceptor stimulation may result from cyclic alterations in arterial blood pressure induced by the respiratory effect on venous return

You can refer to the wikipedia article about this:
http://en.wikipedia.org/wiki/Respiratory_sinus_arrhythmia

[orthopod]

omg so detailed..hahahah..so far i only know a single thing abt reading ecg's .My sister said if there something u need to know then please know abt atrial fibrillation..but then im just 2 days into med school..

[youngyew]

Haha I reckon one single thing which is most important in ECG is to recognise ST elevation in heart attack. But that's quite easy so no worries about that.

[Miracle_seed]

I'm still wondering... Do we study about ECG in SPM or STPM? :huh

[DonFrank]

I'm still wondering... Do we study about ECG in SPM or STPM? :huh

We are not required to study ECG. Just know that such things exist.

http://www.netdoctor.co.uk/health_advice/examinations/ecg.htm
This web gives a good insight on ECG