Methods
We carried out a retrospective analysis of all acute admissions of patients on donepezil treatment to our institution between March 2019 – March 2020. An admission resting 12-lead ECG was obtained and compared to their ECG prior to commencement of donepezil therapy. All data were collected from our local hospital electronic care record and memory clinic database. Patient characteristics and demographics were recorded, including indications for donepezil, comorbidities and left ventricular function (assessed using the Simpson’s biplane method on images obtained from a recent transthoracic echocardiogram). Baseline serum electrolytes (magnesium, adjusted calcium and potassium) and thyroid status were noted. Medications with potential side-effects on cardiac conduction or known to cause electrolyte disturbances, including beta-blockers, levothyroxine, rate-limiting calcium-channel blockers, diuretics, digoxin, tricyclic antidepressants, antipsychotics and selective serotonin reuptake inhibitor (SSRI)/selective serotonin noradrenaline reuptake inhibitor (SNRI) antidepressants were all recorded. In addition, the duration of donepezil therapy was established and rounded off to the nearest year.
Exclusion criteria included recent initiation of donepezil therapy (<6 months), patients with electrolyte disturbances or deranged thyroid function on admission, patients with a paced rhythm on ECG and those patients in whom an ECG prior to commencement of therapy could not be obtained.