The risk of rapid VT/VF was significantly greater ( in both ischemic and nonischemic patients ) when NSVT was observed ( HR 2.06 ; 95 % CI : 1.30-3 .26 ; P = 0.002 in ischemic patients ; HR 3.09 ; 95 % CI : 1.80-5 .28 ; P < 0.001 in nonischemic patients ) .