RESULTS	Mean 24h survival rates of bystander witnessed events showed differences between waveforms in the early circulatory phase at 4-10 min post event ( mean ( S.D. ) RLB 0.45 ( 0.07 ) versus MDS 0.31 ( 0.06 ) , p = 0.0002 ) and demonstrated decline as time to first shock increased to 20 min .\