7 lines (6 with data), 254 Bytes

m278b 0 128 0 10:15:00 25/12/1989
# Start time=10:15
# First beat=10:15:00.171
# <age-range>: 55-59, <sex>: Male, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.421,  <RR-high-limit(sec)>: 1.101
# Note: reel-to-reel recording, not flutter-compensated