Editing Sinus node dysfunction (section)

{{Infobox medical condition
| name          = Sinus node dysfunction
| synonyms      = '''Sick sinus syndrome''' or '''sinoatrial node disease'''
| image         = ECG Sinus Pause.jpg
| caption       = Telemetry strip of a 44-year-old female with asymptomatic sinus pause found while admitted for mildly symptomatic COVID-19 pneumonia.
| field         =
| complications = Tachycardia-bradycardia syndrome
| alt           =
| treatment     =[[Pacemaker]] implantation
| diagnosis       = [[electrocardiogram]]
}}
'''Sinus node dysfunction''' ('''SND'''), also known as '''sick sinus syndrome''' ('''SSS'''), is a group of abnormal heart rhythms ([[Heart arrhythmia|arrhythmia]]s) usually caused by a malfunction of the [[sinus node]], the heart's primary pacemaker.<ref name="Kusumoto2019">{{cite journal |vauthors=Kusumoto FM, Schoenfeld MH, Barrett C, Edgerton JR, Ellenbogen KA, Gold MR, Goldschlager NF, Hamilton RM, Joglar JA, Kim RJ, Lee R, Marine JE, McLeod CJ, Oken KR, Patton KK, Pellegrini CN, Selzman KA, Thompson A, Varosy PD |title=2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society |journal=Circulation |date=20 August 2019 |volume=140 |issue=8 |pages=e382–e482 |doi=10.1161/CIR.0000000000000628 |pmid=30586772 |display-authors=6|doi-access=free }}</ref><ref name="Dobrzynski2007">{{cite journal |vauthors=Dobrzynski H, Boyett MR, Anderson RH |title=New Insights Into Pacemaker Activity: Promoting Understanding of Sick Sinus Syndrome |journal=Circulation |date=10 April 2007 |volume=115 |issue=14 |pages=1921–1932 |doi=10.1161/CIRCULATIONAHA.106.616011 |pmid=17420362 |doi-access=free }}</ref> '''Tachycardia-bradycardia syndrome''' is a variant of sick sinus syndrome in which the arrhythmia alternates between fast and slow heart rates.<ref name="Tse2017">{{cite journal |vauthors=Tse G, Liu T, LiKH, Laxton V, Wong AO, Chan YW, Keung W, Chan CW, Li RA |title=Tachycardia-bradycardia syndrome: Electrophysiological mechanisms and future therapeutic approaches (Review) |journal=International Journal of Molecular Medicine |date=March 2017 |volume=39 |issue=3 |pages=519–526 |doi=10.3892/ijmm.2017.2877 |pmid=28204831 |pmc=5360359 |display-authors=6}}</ref>