encainide and flecainide accounted for the excess of deaths from arrhythmia and nonfatal cardiac arrests ( 33 of 730 patients taking encainide or flecainide [ 4.5 percent ] ; 9 of 725 taking placebo [ 1.2 percent ] ; relative risk , 3.6 ; 95 percent confidence interval , 1.7 to 8.5 ) .
C0003811
arrhythmia
C0085251
encainide