title: A clinicopathological study on the sick sinus syndrome.
abstract: A total of 6 cases of sick sinus syndrome were presented, including 2 cases of sinoatrial (SA) block and 4 cases of bradycardia-tachycardia syndrome. There were 2 men and 4 women, and their ages ranged from 69 to 91 years. Electrophysiological studies were performed in 3 cases, showing positive overdrive suppression in 1 and normal atrioventricular (AV) conduction in 3. Syncopal attacks were found in 4 cases, and 2 cases died suddenly. Histological examination of the SA node and AV conduction system disclosed (1) marked reduction of the SA nodal muscle fibers by 70 t0 80%, (2) moderate to marked proliferation of connective tissues in the SA node, and (3) moderate fibrosis in part of the left bundle branch. The SA node artery was patent.
mesh_terms: D000368:Aged; D001283:Atrioventricular Node / Q000473:pathology; D001919:Bradycardia / Q000473:pathology*; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000473:pathology*; D006329:Heart Conduction System / Q000473:pathology*; D006801:Humans; D008297:Male; D012848:Sinoatrial Block / Q000473:pathology*; D012849:Sinoatrial Node / Q000473:pathology; D013577:Syndrome; D013610:Tachycardia / Q000473:pathology*