Publications

Background specific hea rt rate parameters notably associate with variab le risks of cardiovascular disease and mortal-ity, however, to date there are no readily available blood tests associated with these parameters. Because of the estab-lished parasympathetic contributions towards cardiac regulation, we challenged the working hypothesis that serum acetylcholinesterase (AChE) activity is involved. Methods A total of 403 Healthy men and women were included in the study and underwent treadmill exercise testing. Prior to exercise testing the subject’s serum AChE activity levels were assessed by measurin g r ates o f acetylt hi oc ho li ne hydrolysis. Results In male subjects AChE activity was positively cor-related to resting heart rate (r = 0.210, p = 0.001). Complementing this observation, AChE activity was negatively correlated to the exercise-induced heart rate increase (r = –0.181, p = 0.005) and to heart rate recovery at 1, 2 and 5 minutes following cessation of exercise (r = –0.150, p = 0.022; r = –0.157, p = 0.016; r = –0.176, p = 0.008 respec-tively). This indicated that lower than average AChE activities, which presumably reflect increased peripheral ACh levels, might be correlated to favorable heart rate parameters. Similar observations were made in female subjects, ex-cept for lack of correlation to their resting heart rate. Additionally, we observed that we were able to stratify subjects into two groups of significan tly d ifferent AChE activity (p = 0.001 ) ba sed on a cut poin t of h eart ra te reco very belo w 20 beats one minute after cessation of exercise. Conclusion In asymptomatic individuals lower than average AChE activity is associated with favorable indices of exercise-inducible heart rate increase as well as heart rate recovery. Future studies will be needed to evaluate the added prognostic significance gained by implementing this marker into routine practice.