7 lines (6 with data), 254 Bytes

m265b 0 128 0 15:19:00 02/02/1991
# Start time=15:19
# First beat=15:20:36.773
# <age-range>: 70-74, <sex>: Male, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.554,  <RR-high-limit(sec)>: 1.671
# Note: reel-to-reel recording, not flutter-compensated