7 lines (6 with data), 248 Bytes

m124a 0 128 0 16:00:00 17/05/1991
# Start time=16:00
# First beat=16:00:00.539
# <age-range>: 60-64, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.414,  <RR-high-limit(sec)>: 0.828
# Note: reel-to-reel recording, not flutter-compensated