EXTENT OF SINOATRIAL AND ATRIOVENTRICULAR NODAL DEPOSITS IN CARDIAC AMYLOIDOSIS : A CORRELATIVE INVESTIGATION

Objectives. We morphometrically determined the relative area of amyloid deposition (%D) in sinoatrial and atrioventricular nodes in cardiac amyloidosis. Materials and Methods. We divided 13 hearts with amyloidosis and arrhythmia (arrhythmia group) and 4 hearts with amyloidosis and no arrhytimia (controls) into subgroups. The arrhythmia group included 3 patients with sick sinus syndrome (SSS), 3 with atrioventricular (AV) block, 9 with bundle branch block, 7 with atrial fibrillation, and 4 with ventricular arrhytlnnias. Among all 17 cases, 14 represented primary (AL) amyloidosis and 3 represented secondary (AA) amyloidosis. We selected five microscopic fields for each case and node for quantitative analysis with an image analyzer to determine %D. Results. The %D in both nodes was similar between control and arrhythmia groups. Only in the AV block subgroup was the %D in the sinoatrial node significantly greater than controls (p<0.05), although %D in the SSS subgroup showed some tendency to be greater than in controls. In the atrioventricular node, %D in the AV block subgroup tended to be greater than in controls. The %D was similar between the two nodes for groups with ALλ, ALκ, and AA amyloid, while %D tended to be greater in the AL group than in the AA group. Conclusion. Although a close relationship was not decisively demonstrated between arrhytimias and extent of amyloid deposition in sinoatrial or atrioventricular nodes, SSS might be caused by amyloid deposition in the sinoatrial node and AV block might be caused by amyloid deposition in the atrioventricular node