ACE and hydrops fetalis: Those not using ACE inhibitors or angiotensin receptor blockers had more clearly decreased HF in association with long-range transported PM than all subjects [at lag 2: −1.25; 95% confidence interval (CI), −2.09 to −0.41; at lag 3: −1.1; 95% CI, −2.04 to −0.26], but same kind of modifying effect was not observed for other sources or SDNN.