7 lines (6 with data), 251 Bytes

m138a 0 128 0 16:07:00 14/01/1990
# Start time=16:07
# First beat=16:08:40.250
# <age-range>: 45-49, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.64,  <RR-high-limit(sec)>: 1.085
# Note: recording with a timing signal, flutter-compensated