Treatment of persistent sinus bradycardia with intermittent symptoms: are guidelines clear?

There is uncertainty in the aetiology of syncope in subjects with persistent sinus bradycardia (SB) (sick sinus syndrome). The results of pathophysiological studies suggest a reflex origin of syncope in the vast majority of subjects with SB. From a nosological point of view, 'syndrome' is defined as the association of signs and symptoms that have a pathophysiological correlation. Since in most cases the causal relationship between syncope and persistent SB appears very weak, 'reflex syncope with associated SB' appears to be the most appropriate diagnosis.