7 lines (6 with data), 252 Bytes

m269a 0 128 0 21:30:00 10/01/1991
# Start time=21:30
# First beat=21:30:23.460
# <age-range>: 60-64, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.507,  <RR-high-limit(sec)>: 0.914
# Note: recording with a timing signal, flutter-compensated