7 lines (6 with data), 250 Bytes

m211a 0 128 0 16:30:00 07/05/1990
# Start time=16:30
# First beat=16:37:30.320
# <age-range>: 65-69, <sex>: Female, <medication>: None
# <RR-low-limit(sec)>: 0.539,  <RR-high-limit(sec)>: 1
# Note: recording with a timing signal, flutter-compensated