Cardiac pathology and stress-induced sudden death in CnB1fl/flαMHC-Cre mice. A, Masson's trichrome staining of heart histological sections from 3-month old WTαMHC-Cre and CnB1fl/flαMHC-Cre mice. B, quantification of fibrosis in Masson's trichrome-stained histological heart sections described in A (n = 3 mice in each group, *, p < 0.05). C, survival rate in 2-month-old WTαMHC-Cre (n = 4) and CnB1fl/flαMHC-Cre mice (n = 7) subjected to TAC (p < 0.0001). D, survival rate in 2-month-old WTαMHC-Cre (n = 7) and CnB1fl/flαMHC-Cre (n = 9) mice implanted with Alzet minipumps releasing Iso (60 mg/kg/day, p < 0.05). E, survival rate in 2-month-old WTαMHC-Cre (n = 6) and CnB1fl/flαMHC-Cre mice (n = 6) implanted with Ang/PE containing Alzet minipumps (Ang/PE, respectively, 432 μg/kg/day and 100 mg/kg/day, p < 0.03). F, survival curve in 2-month old WTαMHC-Cre (n = 8) and CnB1fl/flαMHC-Cre mice (n = 10) subjected to 3 weeks of daily swimming. G and H, immunohistochemical assessment of apoptosis by TUNEL in the hearts of WTαMHC-Cre and CnB1fl/flαMHC-Cre mice subjected to 1 day of TAC (G) or Iso infusion (H) (at least 100,000 nuclei were counted; n = 3 mice in each group, *, p < 0.05 versus sham; #, p < 0.05 versus WT Iso).