7 lines (6 with data), 252 Bytes

m143a 0 128 0 10:00:00 08/04/1990
# Start time=10:00
# First beat=10:08:19.773
# <age-range>: 65-69, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.382,  <RR-high-limit(sec)>: 0.976
# Note: recording with a timing signal, flutter-compensated