7 lines (6 with data), 252 Bytes

m275a 0 128 0 10:14:00 11/03/1991
# Start time=10:14
# First beat=10:22:05.562
# <age-range>: 70-74, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.531,  <RR-high-limit(sec)>: 1.328
# Note: recording with a timing signal, flutter-compensated