7 lines (6 with data), 248 Bytes

m273a 0 128 0 15:15:00 12/12/1990
# Start time=15:15
# First beat=15:15:00.031
# <age-range>: 75-79, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.507,  <RR-high-limit(sec)>: 1.046
# Note: reel-to-reel recording, not flutter-compensated