7 lines (6 with data), 252 Bytes

m168a 0 128 0 15:30:00 21/10/1989
# Start time=15:30
# First beat=15:38:05.437
# <age-range>: 60-64, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.609,  <RR-high-limit(sec)>: 1.281
# Note: recording with a timing signal, flutter-compensated