7 lines (6 with data), 252 Bytes

m243a 0 128 0 13:18:00 02/04/1990
# Start time=13:18
# First beat=13:26:20.570
# <age-range>: 65-69, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.585,  <RR-high-limit(sec)>: 1.054
# Note: recording with a timing signal, flutter-compensated