The anatomic substrate for the sick sinus syndrome in adolescence

Enalapril Preserves Sinus Node Function in a Canine Atrial Fibrillation Model Induced by Rapid Atrial Pacing

“…This time course of the development of CSNRT prolongation suggests that not only electrophysiological changes but also additional structural changes might be involved in the sinus node dysfunction in long‐term AF. In the clinical setting, postmortem studies showed deficiency of the nodal cell, fibrosis, and infiltration of fat in and around the sinus node in patients with bradycardia‐tachycardia syndrome 4,7 and long‐term AF 5,8 . A recent study reported a change in the nature of sinus pacemaker activity with loss of the normal multicentric pattern of activation, suggesting loss of automatic pacemaker cells and widespread impairment of sino‐atrial conduction 6 .…”

“…Clinical studies have shown that patients with atrial fibrillation (AF) have a higher incidence of sinus nodal dysfunction 3 associated with significant damage to the sinus node, the perinodal tissue, and the sinus nodal artery 4–6 . Histological examination revealed that fibrosis and fatty degeneration was the main feature of the sinus node lesion 4,7,8 …”

Implications of Marked Fatty Infiltration Around and In the Atrophic Atrioventricular Node in Elderly Patients With Permanent Pacemaker Implantation for Symptomatic Sick Sinus Syndrome

“…Excessive fatty infiltration in the approaches to the AVN and the node itself has also been described in SSS. 7,25,27 and/or the elderly. 28 as yet unexplained.…”

“…34 In addition, the presence of large amounts of fat between myocardial fibers may produce muscle atrophy or be a replacement for degenerated tissue. 27,35 If the approaches to the AVN are completely replaced by fat, various supraventricular arrhythmias and, more rarely, complete AV block may occur. 36 Thus, it is conceivable that SSS and aging interact in some elderly patients with SSS.…”

Sick sinus syndrome in childhood.

“…It is noteworthy that, since the publication ofour paper, similar cases of "isolated" sinoatrial disease have been reported in young boys' and that for the first time an anatomical substrate of this syndrome has been described. 2 On the basis ofthe small number ofpatients reported with this syndrome, we are reluctant to conclude that children behave differently from adults. The impression that their clinical course is more serious may in fact reflect criteria of selection.…”