7 lines (6 with data), 258 Bytes

m248b 0 128 0 13:00:00 21/03/1991
# Start time=13:00
# First beat=13:08:13.132
# <age-range>: 50-54, <sex>: Male, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.484,  <RR-high-limit(sec)>: 1.007
# Note: recording with a timing signal, flutter-compensated