KR-39038 is an orally active and potent GRK5 ( G protein-coupled receptor kinase 5) inhibitor, with an IC 50 of 0.02 μM. KR-39038 significantly inhibits angiotensin II-induced cellular hypertrophy through suppression of HDAC5 pathway in neonatal cardiomyocytes. KR-39038 shows profound anti-hypertrophic effects and improved cardiac function. KR-39038 can be used for heart failure research.