7 lines (6 with data), 252 Bytes

m220a 0 128 0 14:45:00 13/02/1989
# Start time=14:45
# First beat=14:45:34.664
# <age-range>: 65-69, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.523,  <RR-high-limit(sec)>: 1.218
# Note: recording with a timing signal, flutter-compensated