If more than 3 deaths occur in the 1st 20 subjects for any...

If more than 3 deaths occur in the 1st 20 subjects for any reason even if not device related is not clear to me that the 20 subjects were implanted with a c-pulse ? ( subjects ?) it is possible that the four that died were not implanted but were in the 1st 20 ? the FDA have many check measures and would want to confirmation that randomizing the less sick to receive C-Pulse did not occur , hence trigger the automatic pause or halt for the sake of safety , ?