This case report describes an elderly female presenting with simultaneous biliary colic and symptomatic sinus bradycardia. The resolution of her bradycardia with pain management alone suggested Cope's sign, or the cardio-biliary reflex (CBR), as the underlying cause. This reflex is a well-recognized physiological response in which gallbladder pathology triggers vagal nerve signals, potentially causing significant alterations in cardiac rhythm and often mimicking primary heart conditions. This case illustrates that even uncomplicated biliary colic can induce this effect and emphasizes the importance for clinicians to consider this reflex in the differential diagnosis of bradyarrhythmia accompanied by abdominal pain. Recognizing CBR is crucial for directing management toward the correct biliary pathology and avoiding unnecessary cardiac investigations or interventions.