7 lines (6 with data), 250 Bytes

m136a 0 128 0 14:05:00 20/10/1989
# Start time=14:05
# First beat=14:13:53.046
# <age-range>: 50-54, <sex>: Female, <medication>: None
# <RR-low-limit(sec)>: 0.507,  <RR-high-limit(sec)>: 0.875
# Note: reel-to-reel recording, not flutter-compensated