7 lines (6 with data), 254 Bytes

m121b 0 128 0 10:10:00 12/06/1988
# Start time=10:10
# First beat=10:25:20.148
# <age-range>: 70-74, <sex>: Male, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.375,  <RR-high-limit(sec)>: 0.765
# Note: reel-to-reel recording, not flutter-compensated