7 lines (6 with data), 258 Bytes

m238b 0 128 0 14:58:00 26/10/1990
# Start time=14:58
# First beat=15:08:34.906
# <age-range>: 55-59, <sex>: Male, <medication>: Moricizine
# <RR-low-limit(sec)>: 0.382,  <RR-high-limit(sec)>: 1.015
# Note: recording with a timing signal, flutter-compensated