From the Guidelines
Sick sinus syndrome diagnosis and management should prioritize permanent pacemaker implantation with dual-chamber pacing for symptomatic patients, as it has been shown to be highly effective in relieving symptoms and improving quality of life. Diagnosis of sick sinus syndrome requires documentation of symptomatic bradycardia, sinus pauses, or chronotropic incompetence, typically via electrocardiogram (ECG), Holter monitoring, or event recorders 1. Management depends on symptom severity and underlying causes, and dual-chamber pacing (DDD mode) is generally preferred over single-chamber pacing to prevent pacemaker syndrome.
Some key points to consider in the management of sick sinus syndrome include:
- Discontinuation of contributing medications such as beta-blockers, calcium channel blockers, or digoxin if possible 1
- Use of temporary measures such as atropine (0.5-1 mg IV) for acute symptomatic bradycardia or isoproterenol infusion (2-10 mcg/min) in emergency situations
- Consideration of antiarrhythmic medications for patients with tachy-brady syndrome, with options including beta-blockers, calcium channel blockers, or amiodarone 1
- Anticoagulation with direct oral anticoagulants or warfarin for patients with atrial fibrillation based on stroke risk assessment
- Regular follow-up with cardiology to monitor pacemaker function and adjust medications as needed
According to the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay, dual-chamber pacemakers are recommended for treating symptomatic bradycardia due to sick sinus syndrome without atrio-ventricular block 1. This guideline is based on a systematic review and economic evaluation of the available evidence, and provides a comprehensive framework for the diagnosis and management of sick sinus syndrome.
From the Research
Diagnosis of Sick Sinus Syndrome
- Sick sinus syndrome is a collection of disorders marked by the heart's inability to perform its pacemaking function, and its diagnosis can be challenging due to subtle and nonspecific symptoms early on 2, 3.
- The diagnosis is ultimately made by electrocardiographic identification of the arrhythmia in conjunction with the presence of symptoms, and may involve the use of inpatient telemetry monitoring, outpatient Holter monitoring, event monitoring, or loop monitoring if electrocardiography does not yield a diagnosis 2.
- Holter monitoring is important for the diagnosis of sick sinus syndrome and can help select patients for pacemaker implantation 4.
Management of Sick Sinus Syndrome
- The mainstay of treatment for sick sinus syndrome is atrial or dual-chamber pacemaker placement, which can provide effective relief of symptoms and improve quality of life 2, 3.
- Pacemaker implantation is the first-line treatment for symptomatic patients with sick sinus syndrome and documented bradycardia history, and can help reduce the risk of atrial fibrillation, thromboembolic events, heart failure, and mortality 3, 5.
- Catheter ablation may also be used as an alternative second-line therapy for some patients with sick sinus syndrome and atrial fibrillation 5.
Clinical Presentation and Pathophysiology
- Sick sinus syndrome can manifest as diverse cardiac arrhythmias, especially bradycardia, and its clinical presentation is often inconspicuous in the early stage 2, 5.
- Age-related interstitial fibrosis is considered to be the common pathophysiological mechanism between sick sinus syndrome and atrial fibrillation, and the combination of these diseases can adversely affect the condition of patients and the efficiency of subsequent treatment 5.
- The extensive structural and electrical remodeling of the atrium are considered to be the important mechanism for the occurrence of atrial fibrillation in patients with sick sinus syndrome 5.