7 lines (6 with data), 252 Bytes

m112a 0 128 0 10:45:00 13/03/1991
# Start time=10:45
# First beat=10:47:35.242
# <age-range>: 55-59, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.554,  <RR-high-limit(sec)>: 1.179
# Note: recording with a timing signal, flutter-compensated