Sinoatrial disease, also called sick sinus syndrome, results from degenerative changes in the sinoatrial node and is commonest in older people, although it can occur at any age.
Presentation
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Typical symptoms include palpitation, dizzy spells, and syncope.
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Symptoms result from intermittent tachycardia, bradycardia, or pauses in sinus rhythm with no atrial or ventricular activity.
Tachy-brady syndrome
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Sinus bradycardia may coexist with paroxysmal atrial fibrillation. Atrial fibrillation can produce irregular tachycardia if atrioventricular nodal conduction remains brisk; this combination is called tachy-brady syndrome.
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If frailty or other comorbidities make catheter ablation for atrial fibrillation unsuitable, a pacemaker is usually required together with anti-arrhythmic or rate control medication.
Permanent pacing
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Permanent pacing improves symptoms but does not improve prognosis, so it is not indicated in asymptomatic patients.
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A dual-chamber pacemaker is normally used. The right atrial lead assists the sinoatrial node, while the right ventricular lead provides backup if atrioventricular nodal block develops later.