7 lines (6 with data), 250 Bytes

m140a 0 128 0 14:30:00 21/09/1990
# Start time=14:30
# First beat=14:49:18.789
# <age-range>: 60-64, <sex>: Female, <medication>: None
# <RR-low-limit(sec)>: 0.554,  <RR-high-limit(sec)>: 1.132
# Note: reel-to-reel recording, not flutter-compensated