Researchers uncover critical clues about the origin of heart arrhythmias

Study answers decades-old question: Do non-excitable heart cells in the heart directly affect the excitability of the heart?
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Immunofluorescent staining demonstrating fibroblasts expressing the Channelrhodopsin protein in heart scar tissue. The ChR2-expressing fibroblast (green, arrow) is in close proximity to cardiomyocytes (red) within scar.