In a 78‑year‑old man with hypertension, hyperlipidemia and chronic obstructive pulmonary disease who presents with presyncope and light‑headedness and is found to have sinus node dysfunction with symptomatic sinus bradycardia and sinus tachycardia, what is the treatment of choice?

Permanent Pacemaker Placement

In this 78-year-old man with documented symptomatic sinus node dysfunction manifesting as tachy-brady syndrome, permanent pacemaker placement (option e) is the definitive treatment of choice. 1, 2

Rationale for Permanent Pacing

• Symptomatic sinus node dysfunction with documented correlation between symptoms (near-syncope, lightheadedness) and bradyarrhythmias on 48 hours of monitoring represents a Class I indication for permanent pacemaker implantation. 1, 2
• The presence of both symptomatic sinus bradycardia and sinus tachycardia (tachy-brady syndrome) is a specific subtype of sinus node dysfunction that requires pacing to address the bradycardic component. 1, 2
• Extended cardiac monitoring (48 hours plus ambulatory monitoring) has established the critical rhythm-symptom correlation required before proceeding to permanent pacing. 1, 2

Preferred Pacing Mode

• Atrial-based pacing (AAIR or DDDR) is strongly recommended over ventricular-only pacing for sinus node dysfunction with intact AV conduction (Class I, Level B). 1
• Dual-chamber or single-chamber atrial pacing with rate-responsive programming minimizes exertion-related symptoms and accommodates both brady- and tachycardia components. 1, 2
• Atrial-based pacing reduces the incidence of atrial fibrillation, thromboembolic events, heart failure hospitalization, and mortality compared with ventricular-only pacing. 2

Why Other Options Are Incorrect

Cilostazol (option a)

• Cilostazol is a phosphodiesterase-3 inhibitor used for peripheral arterial disease and has no role in treating symptomatic sinus node dysfunction. 1
• Chronotropic agents do not provide reliable, sustained heart rate support for symptomatic bradycardia and should not delay definitive pacing. 2

Digoxin (option b)

• Digoxin is contraindicated in sick sinus syndrome because it can exacerbate bradycardia by depressing sinus node automaticity and AV nodal conduction. 2, 3
• Cardiac glycosides can unmask or worsen underlying sinus node dysfunction. 2, 3

Nifedipine (option c)

• Calcium channel blockers have no therapeutic role in sinus node dysfunction and may worsen bradycardia if non-dihydropyridine agents are inadvertently used. 2
• Even dihydropyridine calcium channel blockers like nifedipine do not address the underlying conduction abnormality. 1

Implantable Cardioverter-Defibrillator (option d)

• ICDs are indicated for prevention of sudden cardiac death from ventricular arrhythmias, not for treatment of sinus node dysfunction. 1
• This patient has no documented ventricular tachycardia, cardiac arrest, or other Class I indication for ICD therapy. 1
• If both pacing and defibrillation were needed, a combined device would be appropriate, but there is no evidence of life-threatening ventricular arrhythmias here. 1

Pre-Implantation Evaluation

• All reversible causes of sinus node dysfunction must be excluded before permanent pacing (Class I). 1, 2, 4
• Review and discontinue or reduce medications that depress sinus node function: beta-blockers, calcium channel blockers, digoxin, amiodarone, sotalol, ivabradine. 2, 4
• Assess for hypothyroidism (TSH, free T4), electrolyte abnormalities (potassium, magnesium), and obstructive sleep apnea if nocturnal bradycardia is prominent. 2, 4
• In this case, the patient's current medications (atorvastatin, lisinopril, tiotropium) do not include agents that cause bradycardia. 1

Expected Outcomes and Follow-Up

• The majority of patients experience significant symptom relief after permanent pacing for symptomatic sinus node dysfunction. 2
• While pacing does not confer a mortality benefit, it markedly improves quality of life and eliminates bradycardia-related symptoms (Class I). 2, 4
• Despite adequate pacing, syncope recurs in approximately 20% of patients during long-term follow-up due to associated vasodepressor reflex mechanisms. 2
• For the tachycardia component of tachy-brady syndrome, catheter ablation may be considered for atrial tachyarrhythmia control after pacemaker implantation. 2, 3

Critical Pitfalls to Avoid

• Do not delay pacing while trialing chronotropic agents such as theophylline in clearly symptomatic patients with documented rhythm-symptom correlation. 2
• Avoid implantation of a ventricular-only (VVI) pacemaker in isolated sinus node dysfunction with preserved AV conduction; atrial-based systems are strongly preferred. 1, 2
• Do not attribute symptoms to non-cardiac causes without proper correlation through extended rhythm monitoring—this patient has already completed appropriate monitoring. 1, 2
• Age alone (78 years) is not a contraindication to pacing when symptomatic and reversible causes have been excluded. 2, 4