FROM FAILURE TO RESQUE: AMINOPHYLLINE IN ATROPINE-RESISTANT BRADYCARDIA – A CASE REPORT

Abstract

Background : Bradycardia with a heart rate below 50 bpm and hypoperfusion, is an emergency condition that requires prompt management. According to ACLS guidelines, atropine sulfate is the first-line medication. This case highlights the role of aminophylline as an alternative therapy in atropine-resistant bradycardia prior to the use of dopamine or epinephrine.

Case Illustration :A 73-year-old woman came to the emergency room with weakness and dyspnea. Physical examination revealed signs of pulmonary edema and hemodynamic instability. An ECG revealed sinus bradycardia with a rate of 24 beats per minute. Laboratory findings suggested an acute exacerbation of chronic kidney disease with hyperkalemia (5.56 mmol/L). The patient was immediately given atropine up to a maximum cumulative dose of 12 ampoules (3 mg), but showed no chronotropic response. Intravenous aminophylline 240 mg was then administered. Following aminophylline administration, the heart rate increased significantly to 82 beats per minute, followed by hemodynamic improvement and gradual resolution of pulmonary edema symptoms.

Discussion: The failure of atropine suggests that the bradycardia is likely mediated by purinergic pathways, rather than simply vagal overactivity. In renal failure and hyperkalemia, cellular metabolic stress leads to increased interstitial adenosine levels, which depress the sinoatrial and atrioventricular nodes via the A1 receptor. Aminophylline acts as a competitive antagonist at this receptor, thus restoring heart rate when parasympatholytic agents fail. Furthermore, aminophylline's potential to increase renal blood flow and its mild positive inotropic effect provide additional benefits in managing fluid overload and pulmonary edema.

Conclusion  : Aminophylline can be considered as another treatment option for atropine-resistant bradycardia prior to the use of dopamine or epinephrine