7 lines (6 with data), 252 Bytes

m042a 0 128 0 10:18:00 12/02/1991
# Start time=10:18
# First beat=10:18:00.539
# <age-range>: 65-69, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.562,  <RR-high-limit(sec)>: 1.187
# Note: recording with a timing signal, flutter-compensated