Clustering of nuclei from the second sample. Uniform Manifold Approximation and Projection (UMAP) projection based on RNA-sequencing of 4,760 PCM1- nuclei from fluorescence-activated cell sorting of a second, separate biopsy from the same heart as in Figure 4. The corresponding dot plot illustrates expression across clusters of preselected, established marker genes representing the major expected cell types in human heart: cardiomyocytes (pink), fibroblasts (red), endothelial cells (yellow), vascular smooth muscle cells and pericytes (cyan), leukocyte populations (green), and neurons (blue).