7 lines (6 with data), 248 Bytes

m146a 0 128 0 11:00:00 19/06/1991
# Start time=11:00
# First beat=11:28:06.523
# <age-range>: 60-64, <sex>: Male, <medication>: None
# <RR-low-limit(sec)>: 0.437,  <RR-high-limit(sec)>: 0.921
# Note: reel-to-reel recording, not flutter-compensated