| Sinus node dysfunction | |
|---|---|
| Other names | Sick sinus syndrome, sinoatrial node disease |
 | |
| Telemetry strip of an asymptomatic sinus pause during COVID-19 pneumonia. | |
| Specialty | Cardiology |
| Symptoms | Few, lightheadedness, palpitations, syncope, chest pain[1] |
| Complications | Atrial fibrillation[2] |
| Usual onset | 68 to 74 years[3][1] |
| Types | Tachy-brady syndrome, atrial bradyarrhythmia, atrial tachyarrhythmia[1][3] |
| Diagnostic method | Based on symptoms and electrocardiogram (ECG)[1] |
| Differential diagnosis | AV block, atrial fibrillation, carotid sinus hypersensitivity[3] |
| Treatment | Avoiding risk factors, pacemaker[1] |
| Frequency | 0.2% of those >65 years[1] |
Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms caused by malfunction of the sinoatrial node, the heart's primary pacemaker.[1] Early on symptoms may be few.[1] As the disease progresses syncope may occur.[1] Other symptoms may include lightheadedness, palpitations, or chest pain.[1] The heart may beat insufficiently fast during exercise.[1] Complications may include atrial fibrillation.[2]
It involves a slow heart rate with or without periods of a faster heart rate.[1] The slow heart rate may be a sinus bradycardia, sinus pause, or sinoatrial exit block.[1] When periods of a fast heart rate is present it is known as tachy-brady syndrome.[1] The underlying mechanism may include fibrosis, ion channel dysfunction, or remodeling of the sinoatrial node.[1] Other factors that can worsen the condition include medications such as beta blockers or calcium channel blockers, electrolyte abnormalities, low oxygen, and low thyroid.[1] Diagnosis is based on symptoms together with electrocardiogram (ECG) findings.[1]
Treatment involves avoiding factors that worsen the condition and placing a pacemaker.[1][4] The typical age of onset is around 68 to 74 years old.[3][1] About 0.2% of people over the age of 65 are affected.[1] Males and females are effected equally frequently.[1] It is the most common reason pacemakers are placed in the United States.[3]
References edit
- ^ a b c d e f g h i j k l m n o p q r s t u Semelka M, Gera J, Usman S (15 May 2013). "Sick sinus syndrome: a review". American Family Physician. 87 (10): 691–6. PMID 23939447.
- ^ a b Tse G, Liu T, LiKH, Laxton V, Wong AO, Chan YW, et al. (March 2017). "Tachycardia-bradycardia syndrome: Electrophysiological mechanisms and future therapeutic approaches (Review)". International Journal of Molecular Medicine. 39 (3): 519–526. doi:10.3892/ijmm.2017.2877. PMC 5360359. PMID 28204831.
- ^ a b c d e Dakkak, W; Doukky, R (January 2020). "Sick Sinus Syndrome". PMID 29261930.
{{cite journal}}: Cite journal requires|journal=(help) - ^ Kusumoto FM, Schoenfeld MH, Barrett C, Edgerton JR, Ellenbogen KA, Gold MR, et al. (20 August 2019). "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". Circulation. 140 (8): e382–e482. doi:10.1161/CIR.0000000000000628. PMID 30586772.