The Application dimension of the Heart Organ Chip market is divided into four primary segments: drug discovery, toxicity screening, disease modeling, and personalized medicine. Drug discovery accounts for the largest share, driven by pharmaceutical firms seeking physiologically relevant cardiac models to accelerate lead optimization and reduce reliance on animal testing. This segment contributes roughly 35 % of total market revenue, reflecting high R&D budgets and the premium pricing of validated platforms. Toxicity screening follows with an estimated 25 % share, as regulatory agencies increasingly require mechanistic cardiac safety data for new compounds; the need for early‑stage cardiotoxicity detection fuels steady adoption. Disease modeling represents about 20 % of the market, leveraging patient‑derived cells to replicate arrhythmias, cardiomyopathies, and ischemic injury, thereby supporting target validation and biomarker discovery. Finally, personalized medicine also captures roughly 20 % of revenue, enabling clinicians to test individualized therapeutic responses on patient‑specific chips. Together, these application categories define the overall market size and underpin the analytical framework of Heart Organ Chip segmentation.