7 lines (6 with data), 248 Bytes

m281a 0 128 0 10:53:00 25/05/1988
# Start time=10:53
# First beat=11:03:27.796
# <age-range>: 65-69, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.492,  <RR-high-limit(sec)>: 0.968
# Note: reel-to-reel recording, not flutter-compensated