7 lines (6 with data), 250 Bytes

m097a 0 128 0 13:05:00 15/02/1990
# Start time=13:05
# First beat=13:06:18.945
# <age-range>: 70-74, <sex>: Female, <medication>: None
# <RR-low-limit(sec)>: 0.789,  <RR-high-limit(sec)>: 1.445
# Note: reel-to-reel recording, not flutter-compensated