Sinus Node Dysfunction.

Sinus node dysfunction (SND) encompasses a broad array of disturbances of sinus node or sinoatrial (SA) function that result in chronic or intermittent periods of slow or fast heart beating.Sinus node dysfunction may be the result of conditions that directly alter sinus node or SA structure, such as ischemic changes, fibrosis or infiltrative diseases, or extrinsic factors, such as drugs or autoimmune disturbances.In children and young adults, intrinsic SA disease has been most commonly associated with presumed direct sinus node damage due to previous atrial surgery, such as closure of atrial septal defects (ASDs), and most importantly, after atrial switch procedures for transposition of the great arteries. However, SND has been observed in patients with unoperated congenital heart disease and even in apparently normal children and adolescents.Thromboembolism is the single most important cause of mortality in SND. Its incidence ranges from 15% to 38%.Regarding therapy of SND, pacemaker therapy may be appropriate in some cases, drug suppression of arrhythmias in others, and both strategies may be required in many individuals.Anticoagulation is critical for treatment of many individuals with SND, particularly those with paroxysmal or persistent atrial fibrillation.In general, pacemaker therapy is indicated and has proven to be highly effective in patients with SND when bradyarrhythmia has been demonstrated to account for symptoms. [ABSTRACT FROM AUTHOR]