7 lines (6 with data), 248 Bytes

m129a 0 128 0 10:00:00 09/06/1991
# Start time=10:00
# First beat=10:20:50.132
# <age-range>: 50-54, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.429,  <RR-high-limit(sec)>: 0.734
# Note: reel-to-reel recording, not flutter-compensated