ABSTRACT
Although the term bradycardia is used to describe any slow heart rhythm, usually under
60 bpm, it is always caused by specific abnormalities in cardiac impulse formation or
conduction. Mean heart rates decline with age, but the prevalence and significance of
bradyarrhythmias in the elderly remain controversial (1-6). Degenerative disease in the
sinus node can lead to pathological sinus bradycardia, sinus arrest, or sinus exit block.
Sick sinus syndrome is a condition that includes one or several abnormalities in sinus
node or atrioventricular (AV) node function. AV block and block in the His-Purkinje
system can occur as a result of ischemic heart disease or various degenerative processes.
Baroreceptor and autonomic abnormalities can produce symptomatic sinus slowing or AV
node block. Bradyarrhythmias are in the differential diagnosis of syncope and presyncope
in the elderly. The identification of bradycardia as a cause of syncope is crucial because
pacemaker therapy usually relieves the problem.
