7 lines (6 with data), 259 Bytes

m280b 0 128 0 8:40:00 22/03/1991
# Start time=08:40
# First beat=08:48:21.601
# <age-range>: 70-74, <sex>: Female, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.484,  <RR-high-limit(sec)>: 1.031
# Note: recording with a timing signal, flutter-compensated