7 lines (6 with data), 260 Bytes

m246b 0 128 0 13:30:00 20/03/1988
# Start time=13:30
# First beat=13:30:15.539
# <age-range>: 70-74, <sex>: Female, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.515,  <RR-high-limit(sec)>: 1.078
# Note: recording with a timing signal, flutter-compensated