BACKGROUND: The SSaSS (Salt Substitute and Stroke Study) has shown that use of a potassium-enriched salt lowers the risk of stroke, total cardiovascular events, and premature death. The effects on cause-specific cardiac outcomes are reported here. METHODS: SSaSS was an unblinded, cluster-randomised trial assessing the effects of potassium-enriched salt compared with regular salt among 20 995 Chinese adults with established stroke and older age and uncontrolled hypertension. Post hoc efficacy analyses were performed using an intention-to-treat method and a hierarchical Poisson regression model adjusting for clustering to obtain rate ratios and 95% CIs. We assessed acute coronary syndrome, heart failure, arrhythmia, and sudden death. RESULTS: Over a mean 4.74 years follow-up, there were 695 acute coronary syndrome events, 454 heart failure events, 230 arrhythmia events, and 1133 sudden deaths recorded. The rates of events were lower in potassium-enriched salt group for all outcomes but CIs were wide for most: acute coronary syndrome (6.32 versus 7.65 events per 1000 person-years; rate ratio, 0.80 [95% CI, 0.65-0.99]); heart failure (9.14 versus 11.32 events per 1000 person-years; rate ratio, 0.88 [95% CI, 0.60-1.28]); arrhythmia (4.43 versus 6.20 events per 1000 person-years; rate ratio, 0.59 [95% CI, 0.35-0.98]); and sudden death (11.01 versus 11.76 events per 1000 person-years; rate ratio, 0.94 [95% CI, 0.82-1.07]; all P>0.05 with adjustment for multiple comparisons). CONCLUSIONS: These results suggest that use of potassium-enriched salt is more likely to prevent than cause cardiac disease but the post hoc nature of these analyses precludes definitive conclusions. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02092090.