Patient presents with complaints consistent with sinus node dysfunction (SND), including bradycardia, fatigue, dizziness, lightheadedness, and syncope.  Symptoms are intermittent and exacerbated by exertion.  Physical examination reveals a heart rate of 55 bpm, regular rhythm, and normal heart sounds.  Electrocardiogram (ECG) demonstrates sinus bradycardia with prolonged sinus node recovery time, consistent with the diagnosis of sick sinus syndrome (SSS).  Differential diagnosis includes other causes of bradycardia such as atrioventricular (AV) block, hypothyroidism, and medication side effects.  Laboratory tests including thyroid function tests and complete blood count (CBC) are within normal limits.  Current medications include lisinopril for hypertension.  The patient denies the use of beta-blockers or other medications that may contribute to bradycardia.  Given the symptomatic bradycardia and ECG findings, the diagnosis of sinus node dysfunction is confirmed.  Treatment options including pacemaker implantation were discussed with the patient.  Risks and benefits of pacemaker therapy were explained, and the patient elected to proceed with pacemaker placement. Cardiology consultation is scheduled, and the patient will be referred for pacemaker implantation. ICD-10 code I49.5, Sick sinus syndrome, is assigned.  This documentation supports medical necessity for the procedure and facilitates accurate medical billing and coding.