7 lines (6 with data), 252 Bytes

m150a 0 128 0 11:30:00 17/06/1990
# Start time=11:30
# First beat=11:32:16.781
# <age-range>: 60-64, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.546,  <RR-high-limit(sec)>: 1.164
# Note: recording with a timing signal, flutter-compensated