View source for Medicine:Sinus arrhythmia

{{Short description|Irregular heart rhythm originating in the sinus node}}
{{Infobox medical condition (new)
 |name          = Sinus arrhythmia
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 |caption       = ECG of a 67-year-old man with sinus arrhythmia, hypertension, diabetes and dyslipidemia.
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 |specialty     = [[Medicine:Cardiology|Cardiology]]
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 |diagnosis     =electrocardiogram
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}}'''Sinus arrhythmia''' is a commonly encountered variation of ''normal'' [[Medicine:Sinus rhythm|sinus rhythm]]. Sinus arrhythmia characteristically presents with an irregular rate in which the variation in the R-R interval vary by more than 0.12 seconds (120 milliseconds). Additionally, P waves are typically mono-form and in a pattern consistent with atrial activation originating from the sinus node.<ref name=":0"/>

== Respiratory sinus arrhythmia ==
During respiration, the intermittent [[Biology:Vagus nerve|vagus nerve]] activation occurs, which results in beat to beat variations in the resting heart rate. During inspiration vagal tone is slowed down and the heart rate goes up (being maximal at the peak of inspiration), while during expiration vagal tone is increased and heart rate decreases, being slowest at end-expiration.<ref>{{Citation |last=Soos |first=Michael P. |title=Sinus Arrhythmia |date=2022 |url=http://www.ncbi.nlm.nih.gov/books/NBK537011/ |work=StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=30725696 |access-date=2022-08-28 |last2=McComb |first2=David}}</ref><ref name=":0">{{Cite web |title=Sinus Arrhythmia - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/medicine-and-dentistry/sinus-arrhythmia |access-date=2022-08-28 |website=www.sciencedirect.com}}</ref>

When present, respiratory sinus arrhythmia typically indicates good cardiovascular health and is more commonly seen in young healthy people, especially those with enhanced vagal tone or slower heart rates.<ref name="Soos2019">{{cite journal | last1=Soos | first1=Michael P. | last2=McComb | first2=David | title=Sinus Arrhythmia | website=NCBI Bookshelf | date=2020-08-24 | pmid=30725696 | url=https://www.ncbi.nlm.nih.gov/books/NBK537011/ |access-date=17 November 2020}} [[File:CC-BY icon.svg|50px]] Text was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref><ref name=":0" />

==See also==
* [[Vagal tone]]

==References==
{{reflist}}

[[Category:Cardiac electrophysiology]]
[[Category:Cardiac arrhythmia]]

{{Sourceattribution|Sinus arrhythmia}}