The normal range and the reproducibility of the cardioinhibitory carotid sinus reflex were studied in 288 apparently healthy subjects of different ages (aged from 17 to 84 yrs., 156 males, 132 females). In each subject we chose the longest RR interval as an activation index of the reflex obtained by carotid sinus massage; its mean value increased slightly with advancing age. In the were 1, 5, 2, 5, 3, 3 sec. respectively, with a 99% confidence limit. No sex difference was found. We studied also a group of 105 @entity1 (aged from 39 to 82 yrs., 67 males, 38 females) with various types of @entity65 , without a previous history of spontaneous @entity1163 . Abnormal maximum RR values were found in 18 of them (17%). This percentage was significantly higher than in normals (2%). In 11 @entity1 (10%) the carotid sinus stimulation evoked a @entity1163 . It seems therefore that a statistically abnormal @entity56 can occur in a substantial number of cardiovascular @entity1 without necessarily leading to spontaneous @entity1163 . Finally the reproducibility of the cardioinhibitory reflex was tested in 42 @entity1 with maximum RR interval values ranging from normal to extremely abnormal. In each subject a significant correlation (r = 0.79) was found between the maximum RR interval values tested in two occasions at intervals ranging from 1 hour to 3 months; besides a concordance in normal or abnormal result was present in 93% of the cases.

[Cardioinhibitory reflex provoked by stimulation of carotid sinus in normal subjects and those with XXXX ].

@entity1 :: ('9606', 'Species') :: ['patients'] @entity56 :: ('MESH:D004342', 'Disease') :: ['carotid sinus hypersensitivity'] @entity1163 :: ('MESH:D013575', 'Disease') :: ['syncopal attack', 'syncope', 'syncopal attacks'] @entity65 :: ('MESH:D002318', 'Disease') :: ['cardiovascular disorders']
@entity65 :: (MESH:D002318,Disease) :: ['cardiovascular disease']
