Histopathological correlates of sinoatrial disease.

Abstract

Six hearts from patients suffering from rhythm disorders consistent with the diagnosis of sinoatrial disease were histologically examined. Four of the patients had shown a tachycardia-bradycardia syndrome, and the remaining two patients episodes of sinus arrest or sinoatrial block with a slow junctional escape rhythm. The rhythm disorders had occurred in the setting of chronic sinoatrial disease (3 cases), acute myocardial infarction (2 cases), and diphtheritic myocarditis (1 case). The abnormalities which were more consistently observed consisted of (1) total or subtotal destruction of the sinus node (6 cases); (2) total or subtotal destruction of the areas of nodal atrial continuity (5 cases); (3) inflammatory or degenerative changes of the nerves and ganglia surrounding the node (6 cases); (4) pathological changes in the atrial wall (5 cases). Chronic or acute lesions involving the AV node, the bundle of His, and its branches or their distal subdivisions were also found in all 6 hearts. The relationship between the observed pathological changes and the physiological disorders are discussed.

Cardiac Lesions in Dairy Cows with Idiopathic Atrial Fibrillation.

“…The histopathologically significant findings common to all the 9 cows with AF were multifocal or fairly large areas of myocardial fibrosis in the right atrium. Fibrotic areas in the atrial myocardium lead to impaired intra-atrial conduction which, in the thin atrial wall, predisposes to inhomogeneity of atrial repolarization or conduction and may thus set the stage for AF [11,13]. In the present series, therefore, it seems reasonable to imagine that the myocardial lesions which constituted anatomical obstacles to conduction in the right atrium created a suitable background for the electrophysiological inhomogeneity favoring the development of AF.…”

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

“…26 Pathological studies have documented diffuse fibrosis of the conduction system in SSS cases. [7][8][9] Although marked fibrosis affected the SAN in most of the 14 cases in the present study, the approaches to the AVN and the node itself were only mildly involved, except in 1 case where the AVN was moderately involved. Instead of finding fibrous lesions, there was marked fatty infiltration in the approaches to the AVN and the node itself in some cases.…”

“…8 Histologic examination reveals widespread fibrosis in the AV conduction system of SSS patients. [7][8][9] An earlier study by Sugiura and Ohkawa, however, demonstrated minor abnormalities at the AVN and the penetrating portion of the …”

Left Atrial Systolic Function Assessed by Left Atrial Ejection Force in Patients with Sick Sinus Syndrome and Paroxysmal Atrial Fibrillation

“…Thery, et al 3) reported that lesions of the atrial muscle such as hemorrhage, fiber degeneration or fibrosis were associated with sinus nodal cell deficiency in 4 of 6 patients with bradycardia-tachycardia. Demoulon, et al 4) also found extensive atrial fibrosis with loss of muscle and architecture in 5 of 6 patients with sinus arrest, sinoatrial block or bradycardia-tachycardia. The present study demonstrated using noninvasive left atrial ejection force (LAEF), that LA systolic function had deteriorated in patients with SSS as well as in those with Paf.…”