7 lines (6 with data), 252 Bytes

m259a 0 128 0 10:20:00 09/11/1989
# Start time=10:20
# First beat=10:21:15.039
# <age-range>: 70-74, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.429,  <RR-high-limit(sec)>: 0.859
# Note: recording with a timing signal, flutter-compensated