Comparative Evaluation of the Effectiveness of Levothyroxine Replacement Therapy After Total Thyroidectomy Using Smart Wristband-Measured Nocturnal Heart Rate and Heart Rhythm Parameters Versus Thyroid Function Tests

Inclusion Criteria

Inclusion Criteria: Age 18 years or older. Undergoing total thyroidectomy at the Department of General Surgery, Yeditepe University Faculty of Medicine Hospital. Initiation of levothyroxine as part of routine postoperative clinical care. Willing and able to attend the routine 1-month postoperative thyroid function test follow-up visit. Willing and able to wear the Xiaomi Smart Band 10 throughout the study period. Able to provide written informed consent. Exclusion Criteria: History of cardiac arrhythmia. Current use of beta-blockers or other antiarrhythmic medications that may affect heart rate. History of heart failure or advanced cardiovascular disease. Diagnosed sleep disorders that may interfere with nighttime heart rate measurements. Pregnancy. Inability or unwillingness to wear the smart wristband as required. Missing clinical or laboratory data required for outcome assessment. Refusal to participate or withdrawal of informed consent.