Timolol-Induced Atrioventricular Block in a Glaucoma Patient: A Case Report

Abstract

Aims: This case report aims to highlight the potential cardiovascular risks associated with timolol, a commonly used medication for the treatment of glaucoma, and to discuss the management of medication-induced atrioventricular (AV) block. It also emphasizes the importance of a multidisciplinary approach in addressing both ophthalmic and cardiovascular issues in patients with comorbidities. Presentation of Case: A 55-year-old woman with a two-year history of primary glaucoma presented to the emergency department (ED) after experiencing dizziness, generalized clonic seizure, and syncope lasting approximately 10 minutes while awaiting a routine ophthalmology appointment. The patient had undergone bilateral trabeculectomy within the past year and had been using timolol 0.5% eye drops twice daily for glaucoma management. On arrival at the ED, the patient was found to have hypotension (85/45 mmHg), bradycardia (34 beats/min), and a 12-lead ECG showed complete AV block with a ventricular escape rhythm. After excluding other causes, including electrolyte imbalances and coronary artery disease, a temporary transvenous pacemaker (TPM) was inserted due to persistent hemodynamic instability. Coronary angiography revealed no significant stenosis, and bedside echocardiography showed normal ventricular function with mild diastolic dysfunction. The patient was ultimately diagnosed with timolol-induced AV block. Given the persistent AV block, a permanent pacemaker was implanted to prevent further episodes of syncope and hemodynamic collapse. Discussion and Conclusion: This case underscores the potential systemic cardiovascular effects of timolol. Timolol, although effective in managing intraocular pressure in glaucoma, can be absorbed systemically and lead to serious side effects such as AV block. The management of AV block in this case required urgent intervention with a temporary pacemaker, followed by permanent pacemaker implantation after the patient's condition remained unstable. A multidisciplinary approach, involving both ophthalmology and cardiology, was crucial in addressing the patient's complex needs. The case also highlights the need for careful monitoring and consideration of alternative glaucoma therapies for patients at risk of medication-induced cardiovascular complications. Timolol's potential risks emphasize the importance of patient education and close monitoring, particularly in vulnerable populations.