7 lines (6 with data), 248 Bytes

m177a 0 128 0 10:27:00 21/02/1989
# Start time=10:27
# First beat=10:27:00.312
# <age-range>: 45-49, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.437,  <RR-high-limit(sec)>: 0.671
# Note: reel-to-reel recording, not flutter-compensated