HEART-RATE AND BLOOD-PRESSURE RESPONSES TO CAROTID-SINUS MASSAGE IN HEALTHY ELDERLY SUBJECTS

The purpose of the study was to define heart rate and blood pressure r esponses to supine and upright carotid sinus massage in healthy elderl y subjects and thus to establish the validity of current diagnostic cr iteria for carotid sinus syndrome in this age group. Twenty-five healt hy asymptomatic subjects (61-87 years) had carotid sinus massage carri ed out following a standardized technique employing previously defined criteria for abnormal heart rate and blood pressure responses: 3 s as ystole and a 50 mmHg fall in systolic blood pressure independent of an y heart rate slowing (after intravenous atropine). No cardioinhibitory responses of greater than 3 s were documented. The mean maximal cardi oinhibitory response was 1038 +/- 195 msec. Right-sided responses were more marked than left when upright (1040 +/- 202 vs. 946 +/- 135 msec ; p < 0.01) but not when supine (1094 +/- 215 vs. 1073 +/- 194 msec; N S). After atropine three subjects (12%) had a significant vasodepresso r response when upright, but none when supine. The mean maximal vasode pressor response was 21 +/- 14 mmHg. Right-sided blood pressure respon ses were more marked than left (p < 0.01). There was no fixed relation ship between maximum heart rate slowing and the degree of vasodepressi on during massage (range 2-80 msec/mmHg). The diagnostic criteria for heart rate and blood pressure responses in carotid sinus syndrome are appropriate for supine carotid sinus massage in elderly subjects. Asym ptomatic vasodepressor responses occur in a small proportion of health y elderly when upright.