7 lines (6 with data), 258 Bytes

m273b 0 128 0 11:15:00 05/01/1991
# Start time=11:15
# First beat=11:15:00.015
# <age-range>: 75-79, <sex>: Male, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.664,  <RR-high-limit(sec)>: 1.039
# Note: recording with a timing signal, flutter-compensated