What medications are used to treat sick sinus syndrome?

Management of Sick Sinus Syndrome

Permanent pacemaker implantation is the definitive treatment for sick sinus syndrome when bradyarrhythmia has been demonstrated to account for symptoms, as it effectively relieves symptoms and improves quality of life. 1

First-Line Treatment: Permanent Pacemaker

Pacemaker Selection

• Physiological pacing (atrial or dual-chamber) is superior to VVI pacing for symptom control and clinical outcomes 1
• Dual-chamber rate-responsive pacemakers (DDDR) are recommended over single-lead atrial pacing (AAIR) due to:
  • Lower risk of pacemaker reoperation (11.9% vs 22.1%) 2
  • Lower incidence of paroxysmal atrial fibrillation (23.0% vs 28.4%) 2
• Atrial-based rate-responsive pacing helps minimize exertion-related symptoms 1
• Newly developed atrial-based minimal ventricular pacing modes are alternatives to conventional DDDR pacing 1

Benefits of Pacemaker Therapy

• Reduces syncope episodes significantly compared to no treatment 3
• Improves quality of life by reducing symptoms like dizziness 1, 4
• Lowers risk of developing atrial fibrillation 1
• May improve survival compared to no treatment, though survival primarily depends on underlying cardiac disease 4
• Associated with lower incidence of heart failure compared to no treatment 3

Important Considerations

• Despite adequate pacing, syncope recurs in approximately 20% of patients during long-term follow-up due to associated vasodepressor reflex mechanisms 1
• Pacemaker implantation is indicated when there is a clear association between significant symptoms and bradycardia 5
• Pacemaker implantation is not indicated in asymptomatic patients with sinus node dysfunction, even with heart rates <40 beats/min 5

Medication Management

Medications to Avoid

• Beta-blockers are contraindicated in patients with sick sinus syndrome 5
• Non-dihydropyridine calcium channel blockers (verapamil, diltiazem) should be avoided 5
• Ivabradine should not be combined with non-dihydropyridine calcium channel blockers 5
• Any medications that exacerbate bradycardia should be eliminated when possible 1

Alternative Pharmacological Approaches

• Theophylline may be considered in selected patients:
  • Associated with lower incidence of heart failure compared to no treatment 3
  • Increases heart rate in patients with sick sinus syndrome 3
  • Less effective than pacemakers in preventing syncope 3
• Atropine may be used temporarily for emergency management of symptomatic bradycardia 5
• Isoproterenol infusion can be used for temporary treatment of refractory symptomatic bradycardia 5

Management of Associated Tachyarrhythmias

• For tachy-brady syndrome (present in at least 50% of sick sinus syndrome patients) 6:
  • Catheter ablation is the first-choice treatment for paroxysmal AV nodal reciprocating tachycardia, AV reciprocating tachycardia, or typical atrial flutter 1
  • For atrial fibrillation or atypical left atrial flutter, treatment should be individualized based on patient characteristics 1
  • Adequate pacing of the heart can help control tachyarrhythmia attacks 7
  • Systemic embolization occurs more frequently in patients with tachy-brady syndrome than in those with bradyarrhythmias alone 4

Special Considerations

• Consider biventricular pacing in patients with depressed left ventricular ejection fraction, heart failure, and prolonged QRS duration 1
• Concomitant disturbances in atrioventricular conduction occur in approximately 35.8% of patients with sick sinus syndrome 4
• The presence of structural heart disease or left ventricular dysfunction may impact prognosis and treatment decisions 1
• Prognosis is mainly determined by the presence or absence of coronary heart disease and/or heart failure 4