This dataset was collected during a prospective phase 2 double-blind randomized placebo-controlled a dose-finding clinical trial to compare the effects of three ascending doses of pyridostigmine (15, 30, and 60 mg three times daily) vs. matching placebo on post-exercise heart rate recovery and other measures of sympathovagal balance. The study included four stages:

1. Screening, randomization, and baseline assessment (visits 1-3)
2. Study drug up-titration (visits 4-7)
3. Study drug maintenance and primary endpoint assessment (Visits 8-9)
4. Study drug down-titration (visits 10-12)

Subjects were eligible if they were ambulatory adults age 21-75 years with left ventricular ejection fraction less than 35% and NYHA Class II-III symptoms despite guideline-recommended medical and device therapy. Study drug was self-administered by the subject at approximately 8-hour intervals (morning dose at 6-8AM, afternoon dose at 2-4PM, and evening dose at 10-12PM). The deceleration in heart rate immediately after exercise was the primary outcome variable. Additional variables collected include oxygen uptake; resting heart rate; heart rate variability; cardiovagal baroreflex function; post-exercise heart rate recovery; and blood analysis.