7 lines (6 with data), 249 Bytes

m233a 0 128 0 9:46:00 19/08/1990
# Start time=09:46
# First beat=09:54:20.968
# <age-range>: 40-44, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.5,  <RR-high-limit(sec)>: 0.984
# Note: recording with a timing signal, flutter-compensated