7 lines (6 with data), 260 Bytes

m189b 0 128 0 15:15:00 11/04/1991
# Start time=15:15
# First beat=15:23:02.804
# <age-range>: 75-79, <sex>: Female, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.781,  <RR-high-limit(sec)>: 1.375
# Note: recording with a timing signal, flutter-compensated