O’Hern et al. present a novel human heart-macrophage assembloid platform generated by integrating hPSC-derived embryonic monocytes into heart organoids. These tissue-resident macrophages regulate cardiac development and conduction and, under chronic inflammation, recapitulate atrial fibrillation features, offering a powerful model to study immune-cardiac interactions and arrhythmia mechanisms.

O’Hern et al. present a novel human heart-macrophage assembloid platform generated by integrating hPSC-derived embryonic monocytes into heart organoids. These tissue-resident macrophages regulate card...