Sinus node dysfunction is often due to degeneration of the heart's impulse-generating system. We report a case of a 40-year-old woman with a recent gastric sleeve surgery, who presented with symptomatic sinus bradycardia following significant post-surgical weight loss. Extensive workup excluded common causes such as electrolyte disturbances, hypothyroidism, or cardiomyopathy. We hypothesize that alterations in leptin metabolism due to weight loss triggered increased vagal stimulation, leading to her bradycardia. The patient was treated with theophylline as a noninvasive alternative to pacemaker implantation. Long-term monitoring showed partial improvement in heart rate. This case highlights the need for vigilance in managing bradycardia as a potential side effect of bariatric surgery-induced weight loss, emphasizing the importance of follow-up and the potential role of leptin in heart rate regulation.