Since the human sinus node is normally located 1 mm. or less beneath the epicardium,1 it must commonly be involved in pericarditis. The potential clinical significance of such involvement is readily apparent. It is surprising, therefore, that the sinus node has received little attention in pericarditis.
In this clinicopathologic study of hearts from 144 patients dying with disturbances of cardiac rhythm or conduction, pericarditis was present in 38. On histologic study of the conduction system the pericarditis involved the sinus node in all 38. Twenty-six of the 38 had documented atrial arrhythmias.
Report of Cases
From these 38 patients with pericarditis (Table) the following 4 are selected as representative. Detailed examples of the histopathology of the sinus node are presented in the first 2.
A 65-year-old man with acute myocardial infarction had intermittent bouts of sinus arrest with an escape nodal rhythm during the week he was