7 lines (6 with data), 252 Bytes

m146b 0 128 0 10:45:00 03/08/1991
# Start time=10:45
# First beat=10:45:01.281
# <age-range>: 60-64, <sex>: Male, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.5,  <RR-high-limit(sec)>: 0.984
# Note: reel-to-reel recording, not flutter-compensated