Third degree atrioventricular block associated with treatment with rivastigmine transdermal patch
Eighty-eight year old female admitted to the coronary care unit following a two week history of dizziness and shortness of breath. The patient had no history of ischemic heart disease and had no chest pain. Extended history revealed she had experienced two inexplicable falling episodes as well as one syncope in the months prior to admission. The cause of these episodes had not yet been investigated. Electrocardiography (ECG) at admission revealed a third degree atrioventricular block with a heart rate of 25–30 beats/min ().\nTwenty-four months prior to admission, the patient was diagnosed with AD with paranoid symptoms in a psychiatric outpatient clinic and started treatment with rivastigmine transdermal patch titrated to 9.6 mg/d, as well as mirtazapine and levodopa. The patient was also treated for hypertension with losartan and a thiazide. ECG at the initiation of rivastigmine therapy showed sinus rhythm, with a heart rate of 67 beats/min. There were no signs of ischemia and no atrioventricular conduction delay. Computer tomography (CT) of the brain at time of initiation of rivastigmine was described as normal. The physical examination at admission revealed no positive neurological deficits save for her known cognitive dysfunction. The patient had normal red and white blood counts, normal creatinine for her age and normal C-reactive protein (CRP) < 10 mg/L. She had slight hyponatriemia of 132 mmol/L (normal range 136−146 mmol/L) and hypocalcemia of 1.12 mmol/L (normal range 1.19−1.29 mmol/L) with normal potassium. Thyroid stimulating hormone was normal. Cardiac biomarkers were slightly elevated at admission with a troponin T of 64 ng/L (upper limit of normal 50 ng/L) and a creatine kinase MB (CK-MB) of 8.4 µg/L (upper limit of normal 4 µg/L). Echocardiography was normal, and the patient was not found a candidate for Coronary Angiography (CAG) due to her general state, and the lack of chest pain. It was concluded by the treating cardiologists that her atrioventricular block was caused by rivastigmine. Rivastigmine was discontinued and the patient received a temporary pacemaker. No other medication was discontinued. After 13 days without resolution of the atrioventricular block, a permanent atrioventricular pacemaker was implanted and the patient was discharged to her own home. Per patient request, rivastigmine was not reinitiated.