How reproducible is the cardioinhibitory response to carotid sinus massage in fallers?

AIMS: To ascertain the reproducibility of the cardioinhibitory subtype of carotid sinus hypersensitivity (CICSH) in fallers. METHODS AND RESULTS: One hundred and seventy-five subjects with CICSH and unexplained or recurrent falls were randomized to pacemaker implantation or control. Sixty-four control subjects (61% female, mean age 71.8 years, median 2 falls in the previous year) completed one-year follow-up and had carotid sinus massage (CSM) performed on 4 occasions (twice before randomization, at 6 months and 1 year following randomization). CSM was performed sequentially on the right and then left sides, initially supine and then upright at 70 degrees head-up tilt by the same investigator. On each occasion CSM was discontinued once CICSH was demonstrated. CICSH was demonstrated on 82% of occasions, 75% on right CSM and 77% whilst the subject was supine. Before randomization, and at 6 months and 1 year, 91%, 67%, and 70% of subjects had reproducible CICSH respectively. Half had CICSH on all 4 occasions. Only 17% had a consistent response on the same side in the same position. CONCLUSIONS: In the majority of subjects CICSH is reproducible and this is more likely shortly after the initial response. However the cardioinhibitory response to CSM is inconsistent both in side elicited and subject position.