Editing Sinus node dysfunction (section)

==Signs and symptoms==
Often sinus node dysfunction produces no symptoms, especially early in the disease course. Signs and symptoms usually appear in more advanced disease and more than 50% of patients will present with [[Syncope (medicine)|syncope]] or transient near-fainting spells as well as [[Bradycardia|bradycardias]] that are accompanied by rapid heart rhythms, referred to as tachycardia-bradycardia syndrome<ref>{{cite journal |vauthors=Hannibal GB, Walsh-Irwin C |title=Sick Sinus Syndrome |journal=AACN Advanced Critical Care |date=1 October 2015 |volume=26 |issue=4 |pages=376–380 |doi=10.1097/NCI.0000000000000099|pmid=26485000 |s2cid=26255262 }}</ref><ref name="Semelka20132">{{cite journal |vauthors=Semelka M, Gera J, Usman S |title=Sick sinus syndrome: a review. |journal=American Family Physician |date=15 May 2013 |volume=87 |issue=10 |pages=691–6 |pmid=23939447}}</ref> Other presenting signs or symptoms can include confusion, fatigue, [[palpitations]], [[chest pain]], [[shortness of breath]], headache, and nausea. Patients can also present with symptoms of [[Heart failure|congestive heart failure]], [[stroke]] or [[transient ischemic attack]]s due to the abnormal rhythm.<ref name="Semelka20132" />

===Complications===
[[File:Brady-tachy syndrome AV-junctional rhythm.png|thumb|[[Electrocardiogram]] from a man with tachycardia-bradycardia syndrome following [[mitral valvuloplasty]], resection of the [[left atrial appendage]], and [[Cox maze procedure|maze procedure]]. The ECG shows [[AV-junctional rhythm]] resulting in [[bradycardia]] at around 46 beats per minute.]] [[Image:Brady-tachy syndrome atrial fibrillation.png|thumb|This ECG from the same patient shows [[atrial fibrillation]] at around 126 beats per minute.]]The most common complication of sinus node dysfunction is the development of tachycardia-bradycardia syndrome with abnormal atrial rhythms such as [[atrial tachycardia]], [[atrial fibrillation]], and [[Atrial flutter|flutter]].<ref name="Semelka20132" /><ref name="Tse2017" /> These rhythms increases the risk of clot formation in the atrium, embolization, and [[stroke]].<ref name="Semelka20132" />

Developing [[sinus arrest]], [[SA block|sinus node exit block]], [[sinus bradycardia]], [[atrioventricular block]], and other types of abnormal rhythms are also common complications.<ref name="Semelka20132" /><ref name="John2016">{{cite journal |vauthors=John RM, Kumar S |title=Sinus Node and Atrial Arrhythmias |journal=Circulation |date=10 May 2016 |volume=133 |issue=19 |pages=1892–1900 |doi=10.1161/CIRCULATIONAHA.116.018011|pmid=27166347 |doi-access=free }}</ref> Sinus node dysfunction has a close association with the presence of [[atrial fibrillation]] due to their shared etiology of remodeling.<ref name="John2016" />