Bradyarrhythmias: sinus node dysfunction.

In the elderly, short asymptomatic episodes of syncope may be caused by many disorders. Therefore, it is essential to obtain ECG evidence of sinus node dysfunction before beginning treatment. Treatment of extrinsic causes of sinus node dysfunction may require removal of a suppressive agent. Medications to suspect include beta blockers, antiarrhythmic drugs, and eyedrops used in the treatment of glaucoma.