7 lines (6 with data), 250 Bytes

m192a 0 128 0 14:15:00 06/11/1990
# Start time=14:15
# First beat=14:51:10.257
# <age-range>: 55-59, <sex>: Female, <medication>: None
# <RR-low-limit(sec)>: 0.507,  <RR-high-limit(sec)>: 0.859
# Note: reel-to-reel recording, not flutter-compensated