7 lines (6 with data), 251 Bytes

m045a 0 128 0 14:15:00 21/04/1990
# Start time=14:15
# First beat=14:23:01.281
# <age-range>: 50-54, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.531,  <RR-high-limit(sec)>: 1.14
# Note: recording with a timing signal, flutter-compensated