7 lines (6 with data), 253 Bytes

m185a 0 128 0 9:50:00 04/10/1990
# Start time=09:50
# First beat=09:55:00.296
# <age-range>: 70-74, <sex>: Female, <medication>: None
# <RR-low-limit(sec)>: 0.468,  <RR-high-limit(sec)>: 0.937
# Note: recording with a timing signal, flutter-compensated