Introduction: Atrial fibrillation is one of the most common arrhythmias occuring in 0.45% of adult population and usually are not assoicated with any cardiac disease. Atrial fibrillation may be seen preoperatively in patients posted for anesthesia.

Case Report: A 48 Vyshya male patient with swelling in the neck, palpitations since two years, hypercalcemia and chronic kidney disease with irregularly irregular pulse (88 per min), BP of 110/60 mmHg and respiratory rate of 20/min. Electrocardiogram showed atrial fibrillation. Echocardiography showed non obstructive hypertrophic cardiomyopathy with dilated left atrium and right atrium , moderate pulmonary artery hypertension with ejection fraction of 60%. Patient was diagnosed to have left parathyroid adenoma and was posted for parathyroidectomy. Serum parathyroid hormone levels was 756 pg/ml. Patient was on Inj. Enoxaparin 40 mg that was stopped twelve hours before day of surgery and Amiodarone 100mg and Metoprolol 25mg which was continued on day of surgery. Continuous ECG, invasive arterial blood pressure, pulse oximetry, capnography, neuromuscular monitoring was done. After preoxygenation, induced with propofol and fentanyl.Intubation done with injection vecuronium. Anaesthesia was maintained with Isoflurane ,oxygen, nitrous oxide and vecuronium. Arterial line was established. Left inferior parathyroidectomy was done in 4 hours. Inj. Amiodarone 3mg/kg diluted in 100 ml normal saline was started before skin incision. Patient was in persistent atrial fibrillation throughout the surgery, extubation was done and the patient was sent to intensive care unit. Conclusion: Patients with atrial fibrillation secondary to hypercalcemia undergoing a crucial non cardiac surgery needs thorough understanding of hemodynamic changes, vigilant intraoperative monitoring with proper preoperative and intraoperative cardiac medication.