7 lines (6 with data), 258 Bytes

m259b 0 128 0 14:08:00 10/12/1989
# Start time=14:08
# First beat=14:16:10.218
# <age-range>: 70-74, <sex>: Male, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.476,  <RR-high-limit(sec)>: 0.851
# Note: recording with a timing signal, flutter-compensated