although there is little doubt that many of the new drugs ( particularly flecainide [ tambocor ] and encainide [ enkaid ] ) are highly effective in suppressing ventricular premature complexes , they should be used with caution , since they also carry a potential for worsening arrhythmia ( proarrhythmic effect ) and congestive heart failure .
C0085251
encainide
C0003811
arrhythmia