7 lines (6 with data), 250 Bytes

f137a 0 128 0 8:45:00 10/02/1988
# Start time=08:45
# First beat=08:52:33.359
# <age-range>: 60-64, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.46,  <RR-high-limit(sec)>: 0.734
# Note: recording with a timing signal, flutter-compensated