Editing Sinus node dysfunction (section)

==Diagnosis==
[[File:ECG Sinus Bradycardia 49 bpm.jpg|thumb|[[Electrocardiography|Electrocardiogram]] (ECG) of a 64-year-old female with [[sinus bradycardia]]. Heart rate 49 bpm.]]

=== Electrocardiogram ===
The primary 12-lead electrocardiogram (ECG) finding in sinus node dysfunction is inappropriate [[sinus bradycardia]].<ref name="Deponti2018">{{cite journal |vauthors=De Ponti R, Marazzato J, Bagliani G, Leonelli FM, Padeletti L |title=Sick Sinus Syndrome |journal=Cardiac Electrophysiology Clinics |date=June 2018 |volume=10 |issue=2 |pages=183–195 |doi=10.1016/j.ccep.2018.02.002 |pmid=29784479 |s2cid=29154542 }}</ref> Sinus node dysfunction can also present with sudden [[Sinoatrial arrest|sinus arrest]] with or without [[Junctional escape beat|junctional escape]], [[sinoatrial block]], prolonged asystolic period followed by tachycardias, or tachycardia-bradycardia syndrome presenting as various atrial arrhythmias such as [[atrial fibrillation]], [[Atrial flutter|flutter]], [[Sinus tachycardia|tachycardia]], or [[paroxysmal supraventricular tachycardia]].<ref name="Deponti2018" /><ref name="Semelka20132" />

=== Clinical diagnosis ===
Diagnosing sinus node dysfunction requires clinical symptoms as well as ECG abnormalities. If ECG findings cannot be identified, prolonged cardiac monitoring should be pursued either with a [[Holter monitor]] in an outpatient setting or telemetry while inpatient, due to the transient nature of abnormal ECG findings.<ref name="Semelka20132" /> If Holter or telemetry monitoring fails to identify ECG changes and suspicion of sinus node dysfunction remains high due to severe symptoms or episodes of syncope, [[implantable loop recorder]]s should be considered for extended monitoring up to 24 months.<ref name="Deponti2018" />

[[Exercise stress test]]s can be utilized to identify intrinsic causes of sinus node dysfunction. [[Tilt table test]]s can be used to discriminate bradycardia caused by dysfunction of the [[autonomic nervous system]].<ref name="Semelka20132" /><ref name="Deponti2018" />