This invention relates to sulfur-substituted phenylacetamides of the formula ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 may be the same or different and are H or CH.sub.3 ; R.sub.4 is SR.sub.5, ##STR2## R.sub.5 and R.sub.6 may be the same or different and are lower alkyl containing 1-4 carbon atoms and R.sub.5 and R.sub.6 may be taken together with S to form a 5-7 member ring; and X.sup.- is a pharmaceutically acceptable anion, which exhibit arrhythmia activity.