Masson trichrome stained sections of sv/+ (A) and sv/sv (B–D) heart. Note the enlargement of the left ventricle (B) and trichrome (blue) stained interstitial and perivascular fibrotic regions in the sv/sv heart (C, D). (E, F)) H&E staining of non-fibrotic (E) and fibrotic regions (F) of sv/sv heart reveals the presence of non-cardiomyocte cells in fibrotic regions. Bar A, B: 1 mm; C, D: 100 μm; E, F: 25 μm.