Sinus Bradycardia Workup and Management

Initial Diagnostic Approach

The American College of Cardiology recommends documenting bradycardia on ECG with heart rate <60 bpm and confirming sinus origin 2
The American College of Cardiology suggests determining if symptoms are directly attributable to bradycardia, including syncope, presyncope, lightheadedness, dyspnea, fatigue, or confusion from cerebral hypoperfusion 1, 3
Asymptomatic bradycardia requires no workup or treatment unless other indications exist, as it is common in athletes, young individuals, and during sleep 2

The American College of Cardiology recommends immediately reviewing all negative chronotropic medications, including beta-blockers, calcium channel blockers, digoxin, sodium-channel blockers, and potassium-channel blocking antiarrhythmics 1, 4, 5
Consider dose reduction or discontinuation if the medication is not essential, such as switching beta-blocker to ACE inhibitor or ARB 1

The American College of Cardiology suggests performing thyroid function tests (TSH, free T4) to identify hypothyroidism, a key reversible cause that responds well to thyroxine replacement 1, 4, 5
Electrolytes (potassium, calcium, magnesium) should be checked, as severe hypokalemia, hyperkalemia, or systemic acidosis can cause bradycardia 1, 5

The American College of Cardiology recommends that electrophysiology study (EPS) should NOT be performed in asymptomatic patients unless other indications for electrophysiological testing exist 1, 4
EPS may be considered (Class IIb) in symptomatic patients with suspected sinus node dysfunction when diagnosis remains uncertain after all noninvasive evaluations 1, 4, 2

The American College of Cardiology emphasizes that the most important error is failing to identify reversible causes before considering permanent pacing, and aggressive investigation for medications, hypothyroidism, electrolyte abnormalities, infections, and increased intracranial pressure must be completed first 5
Ensure documented temporal correlation between symptoms and bradycardia before attributing symptoms to heart rate 1