Herein we describe 6 cases of patients with Alzheimer's disease presented with syncope, dizziness, and dyspnea soon after the initiation of cholinesterase inhibitor therapy. All patients had bradyarrhythmia on electrocardiogram (ECG). Two patients had complete atrioventricular block, 2 pateints had 2/1 type atrioventricular block, 1 patient had sinus bradycardia and hypersensitive carotid sinus syndrome, and 1 had sick sinus syndrome. All these patients were treated with pacemaker implantation and the cholinesterase inhibitor therapy continued. At 13-month follow-up, no syncope, dizziness, or dyspnea was reported.