ATM and heart failure: To further investigate whether SSB accumulation in cardiomyocytes plays a causative role in the pathogenesis of heart failure through activating DDR, we crossed Xrcc1αMHC-Cre mice with Atm+/− mutants28, 29 to block persistent DDR and obtained Xrcc1αMHC-Cre; Atm+/− mice (Supplementary Fig. 10a–d).