From the Guidelines
Sick sinus syndrome and tachy-brady syndrome are essentially the same cardiac condition, with sick sinus syndrome being the broader term for dysfunction of the sinoatrial node and tachy-brady syndrome describing the specific pattern of alternating fast and slow heart rhythms. This condition is characterized by a spectrum of sinoatrial dysfunction, ranging from sinus bradycardia to sinus arrest or the development of paroxysmal atrial tachyarrhythmias in patients with sinus bradycardia or sinoatrial block, as described in the guidelines for cardiac pacing and cardiac resynchronization therapy 1. The disorder results from age-related degeneration or fibrosis of the sinoatrial node tissue, causing it to fire irregularly or inadequately, and patients may experience symptoms including fatigue, dizziness, syncope, palpitations, and shortness of breath. Some key points to consider in the management of this condition include:
- The importance of correlating symptoms with specific arrhythmias, as noted in guidelines for implantation of cardiac pacemakers and antiarrhythmia devices 1.
- The use of permanent pacemaker therapy, which has been shown to be highly effective in relieving symptoms related to bradycardia, especially when physiological pacing (atrial or dual-chamber) is used, as recommended in guidelines on management of syncope 1.
- The potential benefits of rate-adaptive pacing and the avoidance of VVI or VVIR pacing in patients with sick sinus syndrome, as these may not provide adequate rate response and can increase the risk of developing atrial fibrillation.
- The need to consider the potential effects of medications on heart rate and rhythm, and to avoid or cautiously use drugs that can exacerbate bradycardia, as discussed in the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1. Overall, the management of sick sinus syndrome and tachy-brady syndrome requires a comprehensive approach that takes into account the underlying pathophysiology, symptoms, and potential risks and benefits of different treatment strategies.
From the Research
Definition and Relationship
- Sick sinus syndrome (SSS) and tachy-brady syndrome (TBS) are related but not exactly the same condition, as indicated by 2, 3, 4.
- SSS refers to a group of disorders where the heart's pacemaker function is impaired, leading to various arrhythmias, including bradyarrhythmias and tachyarrhythmias 3.
- TBS, also known as tachycardia-bradycardia syndrome, is a complication of SSS characterized by alternating episodes of tachycardia and bradycardia 2, 5.
Clinical Presentation and Diagnosis
- Both SSS and TBS can present with symptoms such as palpitations, fatigue, lightheadedness, presyncope, and syncope due to abnormal heart rhythms and limited tissue perfusion 4.
- Diagnosis of SSS and TBS can be challenging and may require electrocardiographic identification of the arrhythmia, inpatient telemetry monitoring, outpatient Holter monitoring, event monitoring, or loop monitoring 3.
Treatment and Management
- Treatment of SSS and TBS may involve removing extrinsic factors, pacemaker placement, and rate or rhythm control 3, 6.
- Pacemaker implantation is a common treatment option for SSS, but it has disadvantages such as infection, limited battery life, and dislodgement of leads 2.
- Alternative treatments, such as gene-based bio-artificial sinoatrial node and cell-based bio-artificial pacemakers, are being explored, but their long-term safety and efficacy need to be established 2.