7 lines (6 with data), 251 Bytes

m262a 0 128 0 9:29:00 11/05/1988
# Start time=09:29
# First beat=09:30:29.007
# <age-range>: 55-59, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.421,  <RR-high-limit(sec)>: 1.015
# Note: recording with a timing signal, flutter-compensated