7 lines (6 with data), 250 Bytes

m115a 0 128 0 11:31:00 30/03/1989
# Start time=11:31
# First beat=12:05:02.289
# <age-range>: 70-74, <sex>: Female, <medication>: None
# <RR-low-limit(sec)>: 0.617,  <RR-high-limit(sec)>: 1.531
# Note: reel-to-reel recording, not flutter-compensated