7 lines (6 with data), 252 Bytes

m068a 0 128 0 12:20:00 19/02/1991
# Start time=12:20
# First beat=12:24:02.828
# <age-range>: 70-74, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.507,  <RR-high-limit(sec)>: 1.132
# Note: recording with a timing signal, flutter-compensated